It is logical to believe that there exist millions of planets in the “vicinity” of our part of the universe alone. However, limited due to tools and the extremely vast distances to be dealt with, we have only been to locate about 300 extra-solar planets, and these have been located indirectly. That is, by observing gravitational wobbles by tracking the star over a period of time it can be known if it is tugged at by an object like a planet.
Why is it difficult to Image the actual planets, one might ask? Well the reason is simple, the distances we deal with are so huge the star simply outshines the planet, making it very difficult to image the planets moving around the star. How does one avoid this problem? The idea is very practical. A occulting bar is used to block out the brightest part of the star’s image so that the blinding light is reduced. Other more specialized techniques can improve things by reducing the light further.
Also another strategy used by professional astronomers looking into deep space for planets over the last two decades has been to focus on systems expected around young stars. The reason being that if the formation of the planetary system is recent the planets would be significantly brighter from the heat of their formation. Much like our early solar system. It would be very difficult to look into space for a planet that is nestled in a star system like that of our Sun of today. This is because the planets would be very very faint (as they would be older and hence colder) and hence very very difficult to image.
However for the first time we have ACTUALLY been able to see extra-solar planets. This is a HUGE step, culminating from years of painstaking observations and focus. These planets are gaseous and probably will have no trace of life. However, the fact that we have been able to image them has a LOT of meaning. Some astronomers have said that it might not be very fantastic to think that we might in a very short time vector be able to observe some Earth like planet that is more likely to have life (carbon based, atleast of the type we know), now this is something that one could not even THINK of some years ago. It was probably fantasy to think we could be able to image planets like our own, now suddenly it looks quite possible.
The first image below, taken by the Hubble telescope shows a ring of dust surrounding the star Fomalhaut (derived from the Arabic فم الحوت fum al-ḥawt, meaning “mouth of the whale”) which is only 25 light years away in the constellation Piscis Australis. This star can be seen with the naked eye in the night sky. The lower right inset image is a composite image from the images taken in 2004 and 2006. Paul Kalas and his team of the University of California at Berkeley found out the planet. This planet completes orbit around its star every 872 years.
[Image Source: HubbleSite]
The radial streaks are scattered starlight. The planet’s temperature is 260 degrees, quite cool compared to other exoplanets. This dot is about three times the weight of Jupiter and about three times as far from the star as compared to how far Pluto is from our sun. This dusty ring around Fomalhaut is suspected to be something like the Kuiper belt of our solar system.
This star system was expected to have planets in 2005.
The following is a video on the same:
A ring of dust surrounds the star Fomalhaut. Images taken with the Hubble Space Telescope in 2004 and 2006 show that a white dot just inside the dust ring moved in the intervening two years. Researchers believe the dot is a planet that weighs no more than 3 Jupiter masses and lies about three times as far from its star as Pluto does from the Sun (Courtesy of Paul Kalas/UC Berkeley)
Yet another fantastic finding was the discovery of a planetary trio orbiting the star HR 8799 in the constellation pegasus. About 130 light years away, the planets found are from 7-10 times the size of jovian Jupiter. With the farthest of the lot sitting at a distance of 68 AU from HR 8799 (1 AU is the distance between the earth and the Sun). These planets are still glowing because of the heat resulting from contraction after their formation. Their orbit was measured by far IR techniques at the Keck and Gemini North telescopes in Hawaii.
This near-infrared composite image shows the nearby star HR 8799 (multi-coloured blob) and its three planets (red dots at upper left, upper right and just below the star). The planets are 7 to 10 times as massive as Jupiter (Image: National Research Council Canada).
Wow! I am awed once again by the ability of astronomers to find out even the most obscure of dots amongst a nasty conundrum of dots. And even more by the discovery itself. And let me not talk about the images we have above.
I have always harbored a fantasy, that is to be on the crew of humans who get to travel to such a far off land on a Super Daedalus or Super Orion type space-ship. It would take some years (space-ship time). But ofcourse when I return to Earth I would not find anybody I know. For, centuries would have passed as per Earth time by the time I get back. ;)