## Sunday, 24 May 2009

Numerology is the science of numbers. This science was given an identity of its own by Greek mathematician Pythagoras. It is used as a practical method of understanding your deeper nature. It gives insights into the opportunities that you may encounter in your lifetime. It is a self-help tool that provides meaningful advice for all types of situations.

Anyway, for knowing your numerology readings you have to know your Life Path Number, which is popularly called as ‘Lucky Number’. Here is how to find it.

First write down your date of BIRTH. Then add all the numbers in it. Then you arrive at a sum. Then add the numbers in that sum number. Now you have your Life Path Number.

Example:

If you are born on 9-6-1981 here is the way to find your Life Path Number.

Add all the numbers in the birth date.

9+6+1+9+8+1=34.

34 is the sum number. Add the numbers in it.

3+4=7

7 is your Life Path Number or Lucky Number.

If you don’t know your birth date, you can find out your lucky number from your name. For this, you can use Pythagorean Method. In this method every letter is assigned a number as in the following table.

 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9

To find out your lucky number write down your name first. Assign the number to every letter in your name. Add all the numbers. You will get the sum number. Add the numbers in it. You will arrive at your lucky number.

Example:

To find out the lucky number for the name ‘SUCHETHA RAO’, here is the procedure.

Add the numbers associated with every letter in the name.

1+3+3+8+5+2+8+1+9+1+6= 47

Add the numbers in sum number.

4+7=2

2 is the lucky number for the name ‘SUCHETHA RAO’.

Anyway it is always advisable to follow the first method, which is based on your birth date, to find out your lucky number. It gives you the exact results. Though there are some other ways to find your lucky number this is the best advisable method. The numerology results in this channel are based on your ‘Life Path Number’.

### Reiki - You Can Do it!

Reiki as a preventive and curative medicine

Eastern medical philosophy has always emphasized the superiority of maintaining good health over curing illness. Reiki is a preventive medicine par excellence. But it is even more: When practising Reiki on yourself or others, you experience both its preventive and its curative functions at the same time. If you have a disease, Reiki will cure it, if not, Reiki will promote your health and longevity. This preventive cum curative quality of Reiki makes it a unique healing system.

It is natural to be healthy

It is only when certain parts of our bodies fail to function naturally that sickness occurs. The causes may be from bacteria and viruses, organic (toxins) or psychosomatic.

• Bacteria and viruses are always present in our bodies, but they are kept in check (sometimes even exploited to do useful work for us) as long as our bodies function naturally.
• Toxins are continually clogging our organs, but as long as we function naturally, these toxins will be neutralized by the chemicals produced by our body.
• Our brain is continually stressed, but again, if nature runs its course we will be adequately relieved after sleep and rest.

The Eastern concept of health is also wider than that of the West. To be healthy is not just to be free from disease. A person cannot be called healthy if he/she is often restless, irritable or extremely forgetful, cannot concentrate or sleep soundly, and has no zest for work or play.

How Reiki works and promotes health: Health through Reiki & How to use Reiki.

Reiki Symbols as keys

The Reiki symbols are like keys that open doors to a higher mind. You can also see them as buttons, when you press the button you automatically get a result. In my opinion one of the functions of the Reiki symbols is to instantly override the user's precognition that some things cannot be done (i.e. distance healing). The symbols trigger a belief or intention built into the symbols that helps the user to get the results intended. The different symbols also quickly connect the user to the universal life force.
When a Reiki Master does an attunement and shows the Reiki symbols to a student, the form of the symbol is impressed in the students mind and merges with the metaphysical energies it represents.
When a Reiki practitioner draws, thinks about or visualizes a symbol it will instantly connect to the energies it represents.

The Reiki Symbols

From ancient times whenever someone develops a secret method the one would teach this to the people among family, as a legacy for the later generations of the family living. That idea, not to open to the public and keep that sacred method in the family, is really the past century's bad custom.

In modern days we have to live together. That's going to be the basis of happiness, earnestly wanting social progress.

That's why I definitely won't allow to keep this for myself. Our Reiki Ryoho is a creative idea, which no one has developed before and there is nothing like this in this world. Therefore I am going to open this idea to anybody for the peoples benefit and welfare.

Reiki in the words of the founder Mikao Usui - An Interview.

All this and much more you will find on:
Reiki - You Can Do it! by Goran Sandwall at Reiki.nu.
This site is trying to impart information about Reiki and the healing abilities of this easy to learn system. Highly Recommended!

### Relax and Refresh your Eyes

At first, wash your face and eyes with cold water.
Sink your eyes in the palms of your hands filled with cold water and blink a couple of times.

Massage gently your eyelids and surrounding face.

Palming:
• Cover your eyes with palms of your hands without pressing eyeballs.
• Relax your whole body and watch the darkness a while. The darker the better.
• Try to find a comfortable position when doing this, make sure you are not tensed.
• Darkened room is a good place for palming.

### Daily Rituals to Keep You Balanced

Today, in our too-fast, information-overloaded society, we've lost much of our connection to the earth, to spirit, to nature's cycles, to our own cycles. And yet, we still need things to feed us, to ground us, to give us courage and connection.

Good rituals are essential to our emotional, psychological, and spiritual health. To help reconnect us to the sacred aspects of our lives, we asked three experts on the subject to share everyday rituals that they've created or practice.

"Perfectly Balanced" by Alfred Gockel

1. Welcome the Day
Greeting the new day is ingrained in our collective unconscious. Many ancient cultures had some form of morning ritual, and even now most people have a pattern for starting their day, even if it's coffee from the same cafe. Jane Alexander, author of 20 books on holistic living, including "Spirit of the Home: How to Make Your Home a Sanctuary" built this ritual around the classic yoga Sun Salutation. "I like it because it gives your whole body a vibrant wake-up call," she says.

Intention
To put your mind into a positive frame and prepare your entire body for whatever stresses lie ahead.

Materials
Grapefruit essential oil (or any uplifting aromatherapy oil).

Steps
1. Before getting out of bed, lie quietly for a few moments. Say a word of thanks for this new day, and the gift of life. Dab essential oil on a cloth that you'll use solely for this ritual, and breathe in the aroma.

2. Get up and stand in front of a mirror. Smile at yourself and affirm that this will be a good day, full of blessings, opportunities, and wonder. Say aloud, "I look forward to a wonderful day," or any affirmation with personal significance. If there are difficult meetings or decisions ahead, affirm that you will tackle these with ease: "I will take the challenges of this day in stride."

3. Face east and perform the yoga exercise Sun Salutation.

2. Share the Family Meal
Virtually every culture has a tradition of blessing food, cooking and eating mindfully, and giving thanks for the gift of nourishment, Alexander says.

Intention
To create a setting for nurturing and togetherness.

Materials
Festive table decorations, favorite foods, a candle.

Steps
1. Set a specific day and time for a weekly dinner. Every member of the family, even small children, should be in charge of contributing something -- even if it's just stirring the pot or setting the table. Focus your intention as you chop, mix, and blend.

2. Before eating, light the candle, then hold hands and acknowledge the gifts in your life. Feel free to create a special family blessing. This could take the form of a favorite short poem or saying aloud, "We thank mother earth, the sun, and rain for producing this food, the farmers for growing and harvesting it, and the cook for preparing it."

3. Eat your meal with mindfulness. Encourage silence as everyone savors the taste and texture of their food. Reflect on the long journey from farm to table, and how lucky you are to be eating such delicious, nourishing food. When the meal is finished, blow out the candle.

3. Appreciation/Gratitude Ritual
 For our ancestors, gratitude was a way of life, and as a result, every aspect of life presented an occasion for celebration. Offering gratitude is a way to open yourself up to giving and receiving more blessings. Sometimes it takes a simple ceremony to put us in touch with all we do have in our lives. Make this ritual a part of each day, each month, each year -- or whenever you feel it's time to stop and give thanks.IntentionTo value and honor those you love, including yourself.MaterialsCinnamon (essential oil with diffuser, or sticks with bowl of warm water); paper and pen.Steps1. Pour a few drops of the cinnamon oil into a diffuser or spray bottle, or crush two cinnamon sticks into a small bowl of warm water. Allow the aroma to permeate your space.2. Pick up a pen, sit down at your desk, and make a list of all the family members, friends, and pets that matter the most to you. You could even include material things. By writing one or two reasons why each is important to you, you'll clarify your thoughts and honor the people and things in your life that shouldn't be taken for granted.

4. Sleep Well
Bedtime is a psychically charged time of the day, when we drop our defenses and become vulnerable. This is why most religions have a tradition of bedtime prayers, says Alexander, who drew on various religious practices to create this ritual. "In Kabbalah, it is common to carry out a protection ritual to keep one psychically safe while asleep," she says. Today, she believes, most insomnia and disturbed nights are caused by overactive minds mulling over the day's problems. "This ritual is designed to help prevent that."

Intention
To mark the break from day to night and ease you into a state of physical and mental relaxation.

Materials
Lavender oil, notebook, and writing utensil.

Steps
1. Change (or bathe) with intention. As you take off your clothes, visualize all your daytime anxieties and concerns dropping away. As you wash, imagine that you cleanse away all the negativity of the day.

2. Write down all the positive things that happened during your day.

3. Dab the oil on a handkerchief and place it near the bed. Lie down, breathe in the soothing scent of the oil, and cast your mind back over the day without judgment.

5. Letting Go
Aside from death ceremonies (like funerals), we have few traditional rituals to mark the sad endings we experience during the course of our lives. Try this rite, created by shaman and ritualist Donna Henes, author of "The Queen of Myself: Stepping Into Sovereignty in Midlife" and "The Moon Watcher's Companion."

Intention
To provide closure.

Materials
Personal mementos, cloth, herbs for smudging.

Steps
1. Gather together symbols that represent a situation that has ended, such as rings, photos, keys, business cards, a uniform, or a hospital bracelet.

2. Hold each item in your hand and note its significance to your growth and wisdom. Bless it with gratitude for all the lessons you have learned.

3. Wrap all these remembrances of things past in a cloth. Keep this package in a prominent place as an affirmation of change. When you are ready, bury it. Plant flower seeds on the grave, light the herbs, and wave them over the site.

## Saturday, 23 May 2009

### Timeline of Technology

• 1945 First atomic bomb exploded by the United States
• 1946 First electronic computer (ENIAC)
• 1949 Soviet Union tests atomic bomb
• 1950 First kidney transplant
• 1951 First hydrogen bomb exploded by the United States
• 1953 James Watson and Francis Crick discover DNA
• 1954 Launch of first nuclear submarine
• 1955 First commercial electricity from nuclear power; invention of birth control pill
• 1957 USSR launches Sputnik I
• 1959 Integrated circuit invented
• 1960 Laser invented
• 1961 Yuri Gagarin becomes first man in space
• 1962 Mariner 2 becomes first spacecraft to explore another planet
• 1963 Limited nuclear test ban treaty
• 1964 IBM makes a \$10 million grant to fund the Harvard University Program on Technology and Society
• 1965 Largest power failure in history blacks out NY city
• 1966 B52 carrying four hydrogen bombs crashes near Palomares, Spain
• 1967 The tanker Torry Canyon breaks apart, spills 30 million gallons of crude oil
• 1968 Pope Paul VI rejects use of artificial conception
• 1969 Neil Armstrong becomes first human to walk on moon, EPA begins
• 1970 U. S. Congress kills funding for SST, first Earth Day
• 1971 Founding of the Kennedy Institute of Ethics at Georgetown University
• 1972 U. S. Congress passes Clean Water Act and establishes the Office of Technology Assessment (OTA)
• 1973 First spacecraft to achieve escape velocity from the solar system, Congress passes Endangered Species Act, Arab oil embargo
• 1974 Scientists establish a voluntary moratorium on recombinant DNA genetic engineering
• 1976 First successful landing on Mars
• 1978 Soviet Cosmos 954 with nuclear reactor aboard disintegrates over northern Canada, first test-tube baby, Love Canal, NY is evacuated
• 1979 Partial meltdown at Three-Mile Island
• 1981 Formation of Earth First
• 1982 First artificial heart implanted
• 1983 Wave of computer break-ins by teenage computer hackers
• 1984 Union Carbide plant in Bhopal, India explodes killing more than 2,500 people in the worst industrial accident in history
• 1985 Thinning of ozone layer is reported
• 1986 Space shuttle Challenger explodes, Chernobyl reactor burns
• 1987 Montreal Protocol signed by 24 countries to curtail chlorofluorcarbon production
• 1989 Former president Ronald Reagan, knighted in London and inducted into the French Academy in Paris, praises the democratic impact of the electronic revolution in communications and information technology
• 1990 Switching failure blocks half of all calls for a day on long distance At&T lines
• 1991 Iraq sets fire to oil wells in Kuwait in an act of ecoterrorism
• 1992 Earth Summit in Rio de Janeiro yields international treaty to protect biodiversity
• 1993 U. S. House of Representatives votes 282 to 143 to stop funding the multibillion dollar superconducting supercollider

### Technology and Gadget Predictions for 2050!

We fast forward, 42 years into the future, a bleak vision for some of us when remembering the first “super-computer” as people shrieked and fled in terror, almost convinced that the “super-computer” will dominate human life. But let’s face it, it was the size of a small house and answered algebraic equation’s in minutes, just like the calculator can in seconds.

However, we have pondered and paced the garden thinking of what possible catastrophes can be applauded in 42 years? This is what we came up with:

The Flying Car

Since Moller released its “SkyCar M400X,” in 2003, it has failed to succeed. But this has only opened the door to new technology! Currently, there exists various patented, “Flying Cars”, but, again have failed to “take off” (No pun intended). But on a serious note - we have unearthed and have estimated that by 2050 no current car will be drivable! Now this might be because of the “Carbon Emissions,” law, which might rule out every gas powered vehicle. So move over gas, and welcome “Electric” power. Okay its hardly new, but we have listed an electric car that will give the Dodge Spider a run for its money!

Stop drooling…It’s called the Mazda Kaan, (yes it’s a Mazda) and it is “electric,” but do you want to know the best bit? It can drive up to mega top speeds of 250mph and it is soon appearing in the E1 - the Formula One of electric cars. In case you were wondering what those orange rims are…yep…you’ve guessed it - they’re wheels! So innovation in the making, it won’t be long until this thing will be able to fly.

Holograms

“Introducing, the new (2050) iPhone, with integrated, hologram, voice call.” Can you imagine this by 2050, or perhaps sooner? For many of us who watched the “Obama/McCain,” US election on CNN, we might of noticed a hologram of a female reporter. However, this used a few cameras on a 360 degree axis, and one very large “green screen,” to create the illusion. Nevertheless, it has created some media in the process, and now questions remain…when will we see, and use holograms?

George Lucas might be smug as he created the same techniques on Star Wars!

Teleportation

Ever heard of Quantum Teleportation? Now this is in progress at present and consists of transporting one entity to another geographical location. This may seem impossible but scientific research has found this is quite conceivable indeed.

Okay, all you need to get started is a “Transporter!” This could be anything, from a mobile handset to a complete array of electronic plates and a lot of Duracell batteries. However, silly as it might sound it has surpassed notion and is soon to be in development. So let’s all hope in 2050 teleportation could be made public! On the failier of the big “Red Phone Box.” Blue phone boxes might take their place, in the form of a Dardis.

Eco-Villages

Houses are already failing to meet the needs to be energy efficient so all homes will be totally green by 2050.

A normal house in the city, suburb or country, will predominately look the same. It’ll have solar panel roofing, wind turbines in the yard, a “flying car” landing pad and a garage for your teleport.

However, you will have a house robot that will assist you on your daily errands - helping to take out the garbage, prepare the food, beam up the teleport - practically anything. All you have to do is sit back in your eco home without worrying about the sky high electric bills because you have already invested into solar power.

Toilets

Now that were living in the year 2050 why can’t we have a futuristic toilet…well one for it would be insanely boring! There is no point going into the complexities of the matter when when it comes to using the toilet it is more of a functional experience. Well move over practical as the future is set to put some fun into using the good old lav.

Hold! Aim! Fire! yes, that’s right, its the game that you can pee all over. Play games as you pee, with such classics as “bullseye.” Bare in mind, these games consist of skill, accuracy, and “PE-resistance.” If your stuck on a level be sure not to cheat and peak in another guys urinal it might reap bad consequences…do you think it will catch on in the future? Who knows?! I mean, they made Take That popular again so anything is possible!

Robots

Robots might already be here and especially if you have read my review on Gaj-it “Robots taking over the world.” But today a robot’s limits are only to its creator and whatever its master wants. So far, we have acting robots - I know, it won’t make much of a film - we also have robots which can mimic facial expressions. But when, where, and why, will we get to see and use, a robot that can go to the fridge, pull out a Bud so you can sit back and amuse yourself on the latest release of the PlayStation 27.

However, Robots are picking up pace, and seem to grow immensely superior. So expect Robots to be already here by 2050, and themselves, picking their artificial brains, trying to uncover new technology, before 2050?

007?

Now James Bond has gave such a large contribution, that it deserves a category on its own. But where to start as the list of gadgets and gizmo’s is so vast. When we say that the pen is mightier than the sword, we really mean it!

A watch with a laser on it? not Practical, but I’m sure you’ll find it in everyday use. Rings that can shatter bullet proof glass at a twist. A jet pack, for the business man, to get to work on time. Even X-ray glasses for the shop keeper to keep an eye on those youths exiting his shop. Can we see James Bonds’ array of gadgets in 2050, I think yes!

Computers

Comp…What? That’s right, by 2050, computers will no longer be called “computers”, it will have a new name, which would have already served its purpose. We predict that by 2050, computers will evolved enough that they will be monitoring themselves to find a new product, and we will be sitting back, relaxing and waiting until it does. However, Windows will no longer be call “Windows,” instead it will be called, “force field” because let’s face it, we have all this new technology, that we don’t need glass, Upvc windows any more. We can just deactivate a force field, whenever we want to let a little air in.

We predict that, keyboards will be a thing of the past, and we would use “touch screen,” and with many of us with larger roles in IT, will be using Minority Report style gloves to control programmes.

Fountain of Youth

The secret to eternal youth is out folks. Apparently according to boffins, they have found “growth” cells, which all help us age. What they have done is not remove, but reduced its length in order to help us grow old slowly. Now with that being said, I am currently writing a list called “Technology and Gadgets in 2150,” it might just be possible, that we’re all round then.

Stay tuned into Gaj-it and keep up to date

### Galaxies - Introduction

A galaxy is an organized system of hundreds of millions to thousands of billions of stars, sometimes mixed with interstellar gas and dust.

Our sun and solar system are part of the Milky Way galaxy.

Galaxies can be seen in every direction in space, each with billions of stars. Galaxies often appear to be distinct but fuzzy patches of light.

Charles Messier (1730-1817) cataloged more than 100 fuzzy celestial objects, sometimes called Messier objects, and named M1 to M110.

Dreyer compiled the New General Catalog of nearly 8000 objects around 1900. Most of these fuzzy objects are planetary nebulae and star clusters that are part of our galaxy, but extragalactic objects (or galaxies) were also included.

Nearest neighboring large galaxy = Andromeda Galaxy (M31). The relatively "nearby" Andromeda Galaxy (M31) is about 2.2 million light years away.

The Local Group is a group of our nearest galaxy neighbors, held together by their mutual gravitational attraction. About 20 galaxies are in this area.

### Classification of Galaxies

In the 1920's, Hubble devised a classification of galaxies:
1. Spiral galaxies (30%)
2. Elliptical galaxies (most common - 60%)
3. Lenticular galaxies (transitional orms between sprial and elliptical galaxies)
4. Irregular galaxies (10%)

Spiral galaxies are flat disks with a nuclear bulge, a halo of old stars, and spiral arms with young stars. Some have a bar-shaped concentration of stars in the center (barred spirals). Arms emerge fromt he ends of the bar. Dust is readily visible as dark streaks. The Milky Way galaxy is a spiral galaxy.

Globular clusters encircle spiral galaxies. Elliptical galaxies are spheroidal in shape (elliptical in two dimensions). Old stars are dominant. There is no prominent internal structure. They are circled by a halo of globular clusters. Little or no gas and dust are present. Almost all has been converted into stars.

Irregular galaxies are ot disk-like or spheroidal and have no nucleus. They have a chaotic, irregular appearance. Some have bars, but no arms. Sites of active star formation with young stars and luminous gas clouds. Some very old stars are present in globular clusters.

Examples of irregular galaxies are the Small Magellanic Cloud and the Large Magellanic Cloud.

### universe

Solar Activity Heats Up

August 28 saw a major solar flare erupting from a complex sunspot group crossing the Sun's southern hemisphere. The intensity of the eruption placed it in the most powerful "X" category. The flare was accompanied by a coronal mass ejection (CME) which was clocked at 600 km/hr as it headed past the Earth. This CME passed south of Earth's orbital plane and did not cause any major effects here. However, CMEs that collide directly with the Earth can excite geomagnetic storms, which have been linked to satellite communication failures. In extreme cases, such storms can induce electric currents in the earth and oceans that can damage electric power transmission equipment. Scientists expect to see solar flare-ups daily during the solar max, which is expected in mid-2000.

Leaking Earth Could run dry

Researchers from the Tokyo Institute of Technology say that Earth could be dry and barren within a billion years because the oceans are draining into the planet's interior. They have calculated that about 1.12 billion tonnes of water leaks into the Earth each year. Although a lot of water also moves in the other direction, not enough comes to the surface to balance what is lost. The scientists believe that eventually all of it will disappear. They predict that the Earth's surface will look a lot like the surface of the planet Mars where a similar process seems to have taken place. This research was published in the New Scientist magazine. Mir drifts free

Russian space station Mir has gone into "free drift" mode as control passes to a new onboard computer. The free flight is necessary to reduce power consumption so that Mir can survive for months in space before a possible return by cosmonauts. The last crew left on August 27, just 10 days before Mir would have celebrated 10 years of continuous crewing. The new computer keeps the solar panels pointed at the Sun so Mir's batteries remain charged. Russia is expected to make a decision late this year or early next on whether Mir will remain in orbit. The station costs about \$250 million a year to operate and while this is not too high in space terms, Russia just doesn't have the money.

Shaking Earth

The centuries-old mystery of why the Earth appears to wobble has been solved. Every 1.2 years, the planet appears to move about its axis by about 20 ft at the North Pole, but since discovering the so-called Chandler Wobble in 1891, scientists had been unable to explain it. Now NASA believes that the cause lies in the Earth's oceans. Fluctuating pressure of water on the ocean bed caused by temperature, salinity and current changes - forces the Earth to move slightly on its axis. Atmospheric fluctuations add to the wobble. The findings were made by analyzing data from the International Earth Rotation Service, set up in Paris in 1988.

Moon Magic

The Moon has always been an object of fantasy as well as research but we still don't know exactly how the Earth got its moon.

According to the 'giant impact theory', proposed in the 1970s, the moon was formed after the Earth was hit by a huge object, as big as Mars.

Using the new model, researchers at the Southwest Research Institute and the University of California at Santa Cruz, created high-resolution simulations to show that an oblique impact by an object with 10 per cent of the mass of Earth could have ejected sufficient iron free material into Earth's orbit to eventually coalesce into the moon, while also leaving the Earth with its present mass and correct initial rotation rate.

The simulation also implies that the moon formed near the very end of Earth's formation, some 4.5 billion years ago. The moon is believed to have played an important role in making the Earth habitable because of the stabilizing effect it had on the tilt of Earth's rotation.

New Solar System Is Like Ours

After 15 years of searching, astronomers say they have found an alien planetary system that reminds them a lot of home. This is the first time planet hunters have detected what they believe is a Jupiter-like gas ball orbiting a star much like our Sun, at a distance that allows for the possibility of an unseen Earth-type planet orbiting in between.

In the last decade and a half, scientists have found more than 90 so-called extra-solar planets around stars outside our solar system. But none of these earlier discoveries has held the same potential to answer an essential question: Might there be other Earths in the universe?

"We have a (planetary) system that is maybe not a sibling of the solar system… it might be more accurately classified as a first cousin," Paul Butler of the Carnegie Institution said on Thursday.

Butler and fellow planet-hunter Geoffrey Marcy of the University of California-Berkeley noted that the newly discovered Jupiter-type planet is the third thought to orbit 55 Cancri, a star in the constellation Cancer that can be seen without telescopes or even binoculars. It is about as old – five billion years or so – and about the same size as our Sun. Aside from it known planets, the new planetary system has a tantalizing gap between the new Jovian discovery and two other big gas planets orbiting very close to the star, Marcy said.

There’s a huge region centered at about Earth-Sun distance, and in that gap… an Earth-mass planet could exist … and such a planet would be stable, " he said. "It could persist there for billions of years, so it’s conceivable that this system has rocky planets like Mars, Venus or Earth and we simply can’t detect them," Marcy said.

American space agency NASA has outlined ambitious, long-term plans to explore the planet Mars. It says six major missions will take place in little more than 10 years, with Italy and France also participating. At an annual cost estimated at \$400 million to \$450 million a year for the next five years, the agency will dispatch a combination of orbiting spacecraft and landers to the Red Planet. Then, after 2010, the agency will undertake a mission to bring back samples from Mars. In 1999, NASA lost two Martian missions : the Mars Polar Lander and the Mars Climate Orbiter. The failures were a huge blow and prompted a major review of the way NASA carries through its space operations. The campaign to explore Mars is unparalleled in the history of space exploration. It’s meant to be a robust, flexible, long-term programme that will give the highest chances for success. The new strategy is aimed to answer questions about Mars’ mineralogy, geology and climate history. The idea is to ‘follow the water’ so we may know the answers to far-reaching questions about the red planet humans have asked over the generations: Did life ever arise there, and does life exist there now ?"

Astronomers spot winking baby star

A Sun-like star just out of infancy has winked at astronomers, indicating its eclipse by cosmic dust and rocks, the stuff of which planets like Earth could possibly form, scientists reported on Wednesday.

The star, located in the Unicorn constellation about 2,400 light years from Earth, disappeared from view for regular periods of about 48 days over the past six years. Its disappearance suggested an eclipse, but not a typical one caused by an intervening planet, star or moon.

Only a collection of smaller objects, like dust and rocks, could cause the long eclipse the astronomers saw. Known as KH 15D, the star is only about 3 million years old, a prime age for monitoring by astronomers interested in our solar system's planet-forming past.

"We've monitored thousands of these stars over the years and this is the only that behaves this way," said astronomer William Herbst of Wesleyan University in Connecticut. "Essentially the star winks at us."

The dust that caused the wink is different from the fine interstellar dust that is distributed throughout the cosmos. Herbst said. Its particles are bigger, indicating that it is clumping into what astronomers call a protoplanetary disk - the disk from which planets can form.

"Is there a mass in here that is somehow sculpting the obscuring clouds so that it's producing these rings of material which then circle around the star and alternately block the object? We think that's very possible," Herbst said. There could be two blobs circling the star, or just one, but there is no confirmation as yet of exactly what could be causing this kind of disk to form, said Herbst's colleague Catrina Hamilton.

At just 3 million years old, KH 15D is a cosmic toddler barely out of infancy. By contrast, our solar system is thought to be about 4.5 billion years old. However, some astronomers believe the planets may have begun forming when the Sun was a few million years old.

The disk is forming quite close to the star, closer than the planet Mercury is to the Sun. "The star is ... like the Sun was when it was 3 million years old, so the processes that are going on in this inner disk region, where terrestrial planets would be forming - could be analogous to what was going on with the formation of Earth," Herbst said.

### Galaxies

We live in a spiral galaxy. Our Solar System resides about three quarters of the way out from the centre of our Galaxy, or "Milky Way", in a spiral arm consisting of gas and young stars. However, galaxies exist in several different forms. Elliptical galaxies are large, round, aggregates of predominantly old stars. Spirals, like our Galaxy, possess disks with catherine wheel-like arms that are the sites of ongoing star formation.

An infrared image of our Galaxy taken by the Diffuse Infrared Background Experiment (DIRBE) instrument on the NASA Cosmic Background Explorer (COBE) satellite. The galactic plane runs horizontally along the middle of the image. Absorption by interstellar dust is minimized at infrared wavelengths allowing a clearer view of the plane and centre of our Galaxy.

Irregular galaxies, as their name implies, lack a well defined structure, but usually possess numerous star formation regions and large amounts of gas and interstellar dust (micron sized particles made up of carbon and silicon). Galaxies inhabit variously populated regions of space. The low density regions are well populated by spiral and irregular galaxies, whilst the denser, rich clusters are dominated by elliptical galaxies.

An image of Messier 87, a giant elliptical galaxy in the Virgo cluster.

It has become clear over the last 30 years that extremely dense objects exist both in our Galaxy and in the centres of many nearby galaxies. In our Galaxy (and most likely others) small regions of space weighing more than about 5 of our Suns exist. They consume nearby gas and stars and nothing ever escapes their grasp. In the centres of large galaxies similar regions of space exist that also consume stars and gas. However these regions can weigh as much as several billion (1 billion = 1,000,000,000 or 109) Suns.

This web site will describe the theory and observations of these black holes and recent observations of the centres of galaxies that are providing new ideas about galaxy structure and evolution. The galaxies with these exotic, extremely massive objects at their centres may well be called "Hearts of Darkness".

### Dark Stars, Black Holes

Shine a torch upwards in the night sky. The light travels along a straight line then eventually fades, scattered by dust particles in the air. Travelling at 300,000 kilometres per second light is not hindered by the gravitational field of the Earth that requires an object to travel at least 11 kilometres per second to escape its influence. What mass would Earth need to be to stop the torch light from escaping? Based on Newton's gravitational laws the Earth would need a mass equivalent to 2100 times that of our Sun. Such a massive Earth would not be a very hospitable place to live! The intense gravitational field would crush pre-existing structures. If however we used the existing mass of Earth and could squeeze Earth into a sphere slightly smaller than a golf ball, again, light would not escape from its surface.

Theorists from the late 1930s onward predicted that small sized stellar objects could exist as the final products of stellar evolution. A "star" with a radius of 5 kilometres would need to weigh about 1.7 times the mass of the Sun to stop light escaping from its surface. Did such "dark" stars exist?

A schematic view of the formation of a neutron star. A supernova explosion leaves a massive core of neutrons behind.

The partial answer to this question was the discovery in 1967 of radio pulses that came from rotating neutron stars, or pulsars. Pulsars are extremely small, massive stars made of tightly packed neutrons. They are formed during a supernova explosion which occurs to high mass stars. Since their discovery, over one thousand pulsars in the Galaxy have been discovered. A New Zealand astronomer, Richard Manchester, who works at the Australian Telescope National Facility, is one of the worlds leading researchers of pulsars. Whilst neutron stars or pulsars are extremely massive and small, their largest escape velocity is still only about 80% of the speed of light. So they are close to being dark stars, but not quite!

People have been thinking about "dark stars" for over two centuries! In 1783 the Reverend John Michell delivered a paper to the Royal Society in London announcing that invisible stars may exist if they were massive enough. The Frenchman Pierre Laplace discussed a similar phenomenon several years later. Early this century the German astronomer Karl Schwarzschild succeeded in finding solutions to some outstanding problems in Einstein's theory of General Relativity, which describes gravity. Some solutions of Einstein's equations become infinite (called a singularity) at zero radius. Schwarzschild calculated that a singularity, could exist at a small radius for a very dense object. For the Sun this radius would be 3 kilometres. We know this radius nowadays as the Schwarzschild (or gravitational) radius, and it is that required by an object so that radiation cannot escape from it. In 1933 astronomers Walter Baade and Fritz Zwicky suggested that the remnant of a supernova explosion could be a very dense star composed of neutrons.

An artist's impression of a supernova, the explosion of a star.

In 1939 Robert Oppenheimer and colleagues used quantum theory to determine that stable neutron stars could exist, and then went further, publishing a paper that would become a classic. It described massive stars that, once finished thermonuclear burning, would collapse forever. A physical model for a "dark star" had been found!

A photograph of Supernova 1987A (the bright star lower, right) next to the Tarantula Nebula in the Large Magellanic Cloud. This was taken by Alan Gilmore on the 8th of March 1987 using the 60cm reflector at Mount John University Observatory, Lake Tekapo. The image has been inverted so that bright features appear dark.

Let's stop for a moment. A problem is looming! How would you detect an object whose gravitational field is so great that all radiation (light emitted from a torch is just one type of radiation) cannot escape from it? The answer is that you cannot observe it directly, but possibly indirectly, by observing its effect on surrounding objects.

As it turns out, any star greater than 3 solar masses must eventually form such a "dark star" after thermonuclear reactions have ceased, since no known source of pressure can support it. These objects are called "black holes" and this term was first coined by the physicist John Wheeler.

In 1963 a New Zealand mathematician, Roy Kerr, then working at the University of Texas, found solutions to the general relativistic field equations for the case of a rotating star. Since stars rotate, black holes should rotate, and these solutions were critical in understanding the space-time effects of spinning black holes. A major breakthrough had been made. Kerrs solutions showed that as well as having an event horizon (at the gravitational radius) a spinning black hole had another important horizon, at a greater radius than the event horizon, called the static limit. The region between the event horizon and the static limit is called the ergosphere. Later studies by Penrose, Wheeler, Bekenstein and Hawking amazingly showed that black holes could emit radiation from the ergosphere. In general, the smaller a black hole, the larger the amount of radiation could be emitted. However, even for stellar mass black holes the rate of radiation is very small, so that they exist for hundreds of billions of years.

So, are there any black hole candidates? Yes, there exists strong, indirect, evidence for many. One observational signature is the rapid variation of high energy X-rays from an object. This variation can be caused by a binary star system that consists of a black hole orbiting a very large (supergiant) star. Gas from the supergiant is gravitationally attracted to the black hole and as the gas approaches it heats up to 1 million degrees and emits high energy X-rays. A decrease in the strength of X-rays from the binary system is explained when the black hole goes behind the supergiant during its orbit. Many such binary systems are known. One system, Cygnus X-1, in the northern sky constellation Cygnus, is one of the best candidates for a black hole.

Artist's impression of the Cygnus X-1 binary system, with the supergiant star on the left, and the black hole surrounded by an accretion disk of gas, on the right.

Another strong candidate for a black hole is LMC X-1. LMC stands for Large Magellanic Cloud, a close neighbour galaxy to our Galaxy. LMC X-1 is the strongest source of X-rays in the LMC and it originates from an unusually energetic binary star system. This source is thought to be a normal and compact star orbiting each other, similar to the Cygnus X-1 system. The X-rays shining from the system knock electrons off atoms, causing some atoms to glow noticeably in X-rays. Motion in the binary system indicates the compact star is probably a black hole, since its high mass - roughly five times that of our Sun - should be massive enough to cause even a neutron star to collapse.

An X-ray image of LMC X-1 taken with RÃ¶ntgensatellit (ROSAT).

### Active Galaxies and Central Energy Sources

Many galaxies possess nuclei that emit vast amounts of radiation. The amounts can vary from a small fraction to several thousand times greater than the radiation output of an entire normal host galaxy. In the 1950s and 1960s radio astronomy provided important clues to the nature of such galaxies. Powerful radio sources in the sky were found to be associated with faint elliptical galaxies. Many showed dual lobes of radio emission on opposite sides of the optical galaxy. The radio emission was caused by radiation from high velocity, spiralling electrons in strong magnetic fields. This radiation is called synchrotron radiation. It was quickly realised that the majority of the radiation from such galaxies (called active) was not from stellar sources, but due to this type of high velocity particle emission.

A schematic illustration of synchrotron radiation. Electrons spiral around magnetic field lines emitting photons of radiation.

Some clues indicated the probable extreme power source of activity in galaxies. The radio lobes observed on either side of the optical galaxy were sometimes connected to a small, emission region in the nucleus of the galaxy via narrow, straight jets. Energy arguments suggested that the lobes of emission had to be continually replenished by fast moving electrons. The presence of jets joining the nucleus to the lobes suggested that something in the small nucleus was the energy source. Variability in the optical and radio emission of the nucleus on time scales of hours also suggested a very small energy producing region (of light hours diameter, similar in size to the Solar System).

Cygnus A: An image obtained with the Very Large Array (VLA) radio telescope in New Mexico at a wavelength of 6 centimetres. Note the bright lobes, and narrow jets that point back to the nucleus. The optical galaxy lies well within the radio lobes, centred on the radio nucleus.

It is now generally believed that such activity in galaxies is powered by supermassive objects in their nuclei.

### Supermassive objects or black holes?

The presence of supermassive objects in galaxy centres was first inferred in the late 1970s. Imaging and spectral observations of the nucleus of the large elliptical galaxy in the Virgo cluster of galaxies, Messier 87 (or M87, see image above), by Peter Young and Wallace Sargent and collaborators, suggested the existence of a compact object of 5 billion solar masses within 300 light years of the nucleus. This amount of mass is difficult to explain by normal populations of stars, and many astronomers were convinced that supermassive black holes (SBHs) easily explained the observations.

Further, the very small size and enormous energy outputs of these nuclear regions strongly suggest black hole accretion (mass converted to energy by the extreme gravitational field of the black hole) as the energy source. Rapid progress has been made recently in the study of central regions of galaxies by using the high resolution capabilities of the Hubble Space Telescope (HST) and radio telescopes on Earth. HST is in orbit around the Earth, and is above the atmosphere that blurs ground-based optical telescope images.

HST above the Space Shuttle. The gold panels are solar arrays used to power the telescope. The central white rectangle is the cover of the Wide Field Planetary Camera 2 instrument that has taken many high resolution images of galaxy nuclei.

### A matter of perspective? The Unified Model

It is now apparent that many features of active galaxies are common. A model has been put forward that tries to reconcile the differing properties of activity by assuming that the physical structure in the nucleus of all active galaxies is similar. The "unified model" assumes that all active galaxies possess a SBH surrounded by dust in the shape of a torus (doughnut-like). Relativistic jets (ie. radio jets) if detected will appear at right angles to the major axis of the torus.

Variations to the model include the evolutionary status of the SBH (eg. its mass, possible spin), the type of host galaxy (ie. spiral or elliptical), the accretion rate of fuel (ie. gas, stars) into the nuclear (accretion disk + SBH) region, and importantly, the aspect or orientation of the torus to our line of sight. Such model variations go a long way to explain the variety of physical properties seen in active galaxies.

Schematic diagram, not to scale, of the central region of a Seyfert galaxy illustrating the effect of viewing angle. HBLR/BLR stands for Hidden/Broad Line Region (high velocity gas) close to the nucleus, NLR is Narrow Line Region (low velocity gas). Broad spectral lines are produced by gas clouds with large internal velocities.

By looking along a line of sight into the hole of the torus, we see the highest velocity gas clouds, nearest to the SBH. Such galaxies are classified as Seyfert 1, Quasar and Blazar. If the torus obstructs our direct view, we can only observe lower velocity gas clouds, further from the SBH, and possibly scattered light from the nuclear region, and we then detect active galaxies of the Seyfert 2 and radio galaxy types. In rough order of increasing luminosity the active galaxies are Seyferts, Radio Galaxies, Blazars and Quasars. It is now thought that the host galaxies of Seyferts are spirals, and elliptical galaxies host radio galaxies and quasars although there could be some overlap. Also, many distant quasars imaged by HST show peculiar structures that are indicative of interacting or merging galaxies, suggesting that collisions between galaxies may help to produce the high luminosity quasars.

An artist's impression, based on HST observations, of a warped, dusty disk around a suspected SBH in NGC 6251. Perpendicular to the disk is a jet of relativistic particles ejected along the SBH spin axis.

### Nearby Monsters

NGC 4261 - A large, dusty disk

NGC 4261 is a bright elliptical galaxy. It has radio jets extending well outside the optical galaxy. The HST image shows a large, about 400 light years in diameter, dusty disk slightly inclined to our line of sight. Note that the radio jets are aligned perpendicularly to the major axis of the dusty disk (ie. the extended cool region of a torus) consistent with the unified model. HST spectral observations of gas in the nucleus suggest a 5 x 108 solar mass SBH.

NGC 4261, Left: A ground based composite optical (white) and radio (yellow/orange) image. Right: HST image of the galaxy centre showing the disk of dust. Interestingly, the suspected SBH is some 20 light years from the geometrical centre of the galaxy. The reason for this misalignment is unknown.

A word of warning. Even though HST allows us the clearest optical view of galaxy centres, we do not directly resolve the SBHs or their gaseous accretion disks. For example, NGC 4261 is approximately 82 million light years distant, and at that distance, an SBH accretion disk of 1 light week diameter would span about 1/1000 the size of a HST imaging pixel element. What we do see in HST images however are the cooler, dusty disks surrounding the SBH and hot accretion disk. However, the resolving power of HST does allow important velocity measurements at small distances from the nucleus, which constrains the mass contained within that distance.

Messier 87 - revisited

M87 is one of the nearest ellipticals that shows signs of activity. As long ago as 1918 H. D. Curtis discovered an optical "jet" originating from the nucleus. The optical emission from the jet is also synchrotron radiation, seen usually as radio emission. The synchrotron jet occurs at optical wavelengths when the fast moving electrons are very energetic. M87 is a powerful radio source (known as 3C 274 and Virgo A) and the radio source at the nucleus is compact, spanning a diameter of less than 3 light-months.

M87 as observed by HST showing the nuclear gas disk (lower left) and jet.

HST detects a small disk of gas in the nucleus. The disk is approximately elliptical in shape, and its minor axis is close to the direction of the optical synchrotron jet. Radial velocity measurements along the gas disk shows high recession and approach velocities of 500 kilometres per second. A central mass of 2 billion solar masses is deduced. The authors conclude that the disk of gas is feeding a SBH in the nucleus, consistent with (but smaller than, by a factor of about two) the mass inferred from the measurements in the 1970s mentioned previously.

HST optical observations of M87, showing the nuclear gas disk, and the spectral signature of rotation. A gas emission line from two regions of the disk shows a shift in wavelength indicative of very high relative velocities.

### A Mini-Monster in our backyard!

For a number of years evidence has been growing that the centre of our Galaxy may harbour a SBH. The motions of stars around our Galaxy centre indicate increased velocities down to very small distances, about 10 light days. The density of matter needed to explain such motions rules out most alternatives to a SBH.

Left: A near-infrared image of the central 3 light years of the Galaxy centre. The observation was made with the SHARP I camera on the NTT telescope at ESO, La Silla, Chile. Right: A contour plot of the image. The compact radio source Sgr A*, which is associated with a 3 million solar mass black hole, is just above the central label "SW".

A radio image of the Galactic Centre at a wavelength of 6 cm, taken with the VLA. The region is known as Sgr A West (encompassing Sgr A*) and the emission is due to gas being heated by nearby hot, young stars.

As in the case of stellar mass black hole systems, we may expect to detect large amounts of X-rays from an accretion disk around a Galactic Centre SBH. However, observations have resolved most of the X-ray emission in the region to a handful of unrelated X-ray binary systems. The X-ray luminosity of the Galactic Centre is some 7 orders of magnitude lower than expected for an accretion disk around a 3 million solar mass SBH. It is therefore possible that if a SBH does reside in the centre of our Galaxy, it is dormant.

### Where to now?

The picture that has emerged is as follows. SBHs are probably a normal feature of the central regions of bright galaxies that have spheroidal components (eg. elliptical galaxies, spiral galaxies with a bulges). SBHs have not been detected in irregular galaxies. The SBH masses scale roughly with the mass of the host galaxy, implying a strong link between the growth of the galaxy as a whole, and the growth of the SBH.

Some fundamental questions remain however. What is the link between SBHs seen today in relatively nearby and lower luminosity galaxies to distant, very luminous quasars? Quasars were more populous in the early universe, and so it is possible that many nearby galaxies were quasars in their youth, and now harbour relic SBHs that earlier emitted high (quasar) luminosities. How do SBHs evolve? We also believe that galaxy mergers were more prevalent at earlier times in the Universe. What part then do galaxy mergers play in SBH evolution? How would two pre-existing SBHs behave if their host galaxies merged? Such events may not be observable by the usual optical, radio or X-ray telescopes, but by the detection of gravitational waves. A merger of two 107 solar mass SBHs would radiate energy at a frequency of about 10-4 Hz.

The European Space Agency (ESA) is planning a space-based gravity wave detector, called Laser Interferometric Space Array (LISA). The primary objective of the LISA mission is to detect and observe gravitational waves from massive black holes and galactic binary stars in the frequency range 10-4 to 10-1 Hz. Useful measurements in this frequency range cannot be made on the ground because of the unshieldable background of local gravitational noise. From recent research and upcoming missions like LISA we are finally shining some light on these enigmatic hearts of darkness.

An artist's impression of LISA. It consists of six identical spacecraft forming an equilateral triangle in space with two closely spaced (200 kilometres) "near" spacecraft at each vertex. When a gravity wave passes through the system it causes a strain distortion of space which will be detected by measuring the fluctuations in separation between proof masses inside the spacecraft.

## Friday, 22 May 2009

### Universe Measured: We're 156 Billion Light-years Wide!

f you've ever wondered how big the universe is, you're not alone. Astronomers have long pondered this, too, and they've had a hard time figuring it out. Now an estimate has been made, and its a whopper.

The universe is at least 156 billion light-years wide.

In the new study, researchers examined primordial radiation imprinted on the cosmos. Among their conclusions is that it is less likely that there is some crazy cosmic "hall of mirrors" that would cause one object to be visible in two locations. And they've ruled out the idea that we could peer deep into space and time and see our own planet in its youth.

First, let's see why the size is a number you've never heard of before.

Stretching reality

The universe is about 13.7 billion years old. Light reaching us from the earliest known galaxies has been travelling, therefore, for more than 13 billion years. So one might assume that the radius of the universe is 13.7 billion light-years and that the whole shebang is double that, or 27.4 billion light-years wide.

But the universe has been expanding ever since the beginning of time, when theorists believe it all sprang forth from an infinitely dense point in a Big Bang.

"All the distance covered by the light in the early universe gets increased by the expansion of the universe," explains Neil Cornish, an astrophysicist at Montana State University. "Think of it like compound interest."

Need a visual? Imagine the universe just a million years after it was born, Cornish suggests. A batch of light travels for a year, covering one light-year. "At that time, the universe was about 1,000 times smaller than it is today," he said. "Thus, that one light-year has now stretched to become 1,000 light-years."

All the pieces add up to 78 billion-light-years. The light has not traveled that far, but "the starting point of a photon reaching us today after travelling for 13.7 billion years is now 78 billion light-years away," Cornish said. That would be the radius of the universe, and twice that -- 156 billion light-years -- is the diameter. That's based on a view going 90 percent of the way back in time, so it might be slightly larger.

"It can be thought of as a spherical diameter is the usual sense," Cornish added comfortingly.

(You might have heard the universe is almost surely flat, not spherical. The flatness refers to its geometry being "normal," like what is taught in school; two parallel lines can never cross.)

Hall of mirrors

The scientists studied the cosmic microwave background (CMB), radiation unleashed about 380,000 years after the Big Bang, when the universe had first expanded enough to cool and allow atoms to form. Temperature differences in the CMB left an imprint on the sky that was used last year to reveal the age of the universe and confirm other important cosmological measurements.

The CMB is like a baby picture of the cosmos, before any stars were born.

The focus of the new work, which was published last week in the journal Physical Review Letters, was a search of CMB data for paired circles that would have indicated the universe is like a hall of mirrors, in which multiple images of the same object could show up in different locations in space-time. A hall of mirrors could mean the universe is finite but tricks us into thinking it is infinite.

Think of it as a video game in which an object disappearing on the right side of the screen reappears on the left.

"Several years ago we showed that any finite universe in which light had time to 'wrap around' since the Big Bang would have the same pattern of cosmic microwave background temperature fluctuations around pairs of circles," Cornish explained. They looked for the most likely patterns that would be evident in a CMB map generated by NASA's Wilkinson Microwave Anisotropy Probe (WMAP).

They didn't find those patterns.

Don't look back

"Our results don't rule out a hall-of-mirrors effect, but they make the possibility far less likely," Cornish told SPACE.com, adding that the findings have shown "no sign that the universe is finite, but that doesn't prove that it is infinite."

The results do render impossible a "soccer ball" shape for the universe, proposed late last year by another team. "However, if they were to 'pump up' their soccer ball to make it larger, they could evade our bounds" and still be in the realm of possibility, Cornish said. Other complex shapes haven't been ruled out.

The findings eliminate any chance of seeing our ancient selves, however, unless we can master time travel.

"If the universe was finite, and had a size of about 4 billion to 5 billion light-years, then light would be able to wrap around the universe, and with a big enough telescope we could view the Earth just after it solidified and when the first life formed," Cornish said. "Unfortunately, our results rule out this tantalizing possibility."

Impossible? Cornish Explains Further

Update, 8:25 a.m. Tuesday, May 25

This article generated quite a few e-mails from readers who were perplexed or flat out could not believe the universe was just 13.7 billion years old yet 158 billion light-years wide. That suggests the speed of light has been exceeded, they argue. So SPACE.com asked Neil Cornish to explain further. Here is his response:

"The problem is that funny things happen in general relativity which appear to violate special relativity (nothing traveling faster than the speed of light and all that).

"Let's go back to Hubble's observation that distant galaxies appear to be moving away from us, and the more distant the galaxy, the faster it appears to move away. The constant of proportionality in that relationship is known as Hubble's constant.

"One seemingly paradoxical consequence of Hubble's observation is that galaxies sufficiently far away will be receding from us at a velocity faster than the speed of light. This distance is called the Hubble radius, and is commonly referred to as the horizon in analogy with a black hole horizon.

"In terms of special relativity, Hubble's law appears to be a paradox. But in general relativity we interpret the apparent recession as being due to space expanding (the old raisins in a rising fruit loaf analogy). The galaxies themselves are not moving through space (at least not very much), but the space itself is growing so they appear to be moving apart. There is nothing in special or general relativity to prevent this apparent velocity from exceeding the speed of light. No faster-than-light signals can be sent via this mechanism, and it does not lead to any paradoxes.

"Indeed, the WMAP data [on cosmic microwave background radiation] contain strong evidence that the very early universe underwent a period of accelerated expansion in which the distance been two points increased so quickly that light could not outrace the expansion so there was a true horizon -- in precise analogy with a black hole horizon. Indeed, the fluctuations we see in the CMB are thought to be generated by a process that is closely analogous to Hawking radiation from black holes.

"Even more amazing is the picture that emerges when you combine the WMAP data with [supernova] observations, which imply that the universe has started inflating again. If this is true, we have started to move away from the distant galaxies at a rate that is increasing, and in the future we will not be able to see as many galaxies as they will appear to be moving away from us faster than the speed of light (due to the expansion of space), so their light will not be able to reach us."

## Saturday, 16 May 2009

### SOUL OF PAKISTAN

CLICK NOW
COLLECTION OF WORLD'S BEST WALLPAPERS
WOW WHAT A BEAUTY
AMAZING NATURE
NATURE OF GODCOOL PHOTOS BANK
BEAUTY OF WILDLIFE
BEST PHOTOS OF THE WORLD