|
|
|
Fact is stranger than fiction
As scientists and astronomers explore the final frontier a little more each day, they have to take a step back to marvel at the mysteries of the cosmos
The more we strive to find out about the cosmos, the more puzzling it becomes for us to fully comprehend the universe. With a plethora of state-of-the-art telescopes and probes sent out to discover ‘new’ moons, comets, asteroids and planets, we are still on the threshold of the ‘final frontier’.
In the present century, many science fiction notions have been transformed into facts. Theories and ideas once scoffed at by experts and scientists are now deemed a reality.
No longer is the idea of another Earth-like planet viewed as a fantasy and even prestigious scientific institutions are looking into the possibility of discovering alien life forms. As we come across new facts about the universe, we are forced to shed old theories in favour of new ones.
For instance, the old model of the solar system, with planets orbiting one sun, has been challenged in view of some startling discoveries made in the last few months. Therefore, scenarios like the ones portrayed in the popular sci-fi series Star Trek are no longer imaginary.
In fact, scientific theories now support the idea that there may be planetary systems out there which revolve around more than one sun. Experts assume that more than half the stars in our galaxy have stellar companions.
However, of the 130 planets that have so far been discovered to orbit stars other than our Sun, only 20 have a binary system. Needless to say, the number of such planets is expected to increase.
Recently scientists who regularly try to discover exoplanets (planets that do not revolve around our Sun) met at the Space Science Institute in Baltimore. “A few years ago, it was thought that binaries were a very bad site to search for planets. So we carefully eliminated all binary stars from our sample,” said Michel Mayor of the Observatoire de Geneve.
Previously, researchers simply did not look for binaries as they thought that 2-star systems would hide the signature of any exoplanet looming in the system. Experts now feel that planets, even terrestrial ones, may exist just as well enough in a binary star system as in a single-star system.
“The most significant thing we found is that terrestrial planets around certain close and wide binaries can look similar to planets around a single star,” said Jack Lissauer from the Nasa’s Ames Research Centre. Some systems in which the two suns are far away from each other are called wide binaries. In such a case, planets could orbit any of the stars.
Stars are considered part of wide binaries, the systems in which suns are separated by several AUs (Astronomical Unit, the distance from Earth to the Sun). Planets in such systems either orbit the pair or each sun individually.
Interestingly, the binary systems discovered so far are all wide binaries. On the other hand, planets with close binaries in which the stars are less than 1 AU apart are expected to have planets orbiting both the stars. But these planets are very hard to detect.
Computer simulations
Planet hunters have designed computer simulations with 14 large planet “embryos”. They also included 140 planets, which were smaller in size around one or both of the suns in the binary star systems. The results proved fruitful.
“All of our simulations have been able to form terrestrial planets,” claimed Elisa Quintana, a researcher at Ames. Even then, not all computer models were successful in formulating planets around systems 1AU apart.
The group of researchers also simulated a system similar to Alpha Centauri, which is the nearest binary system to our planet. Here the two stars come as close as 11 AUs. The interesting results proved that terrestrial planets were possible around either of the two stars.
However, so far no planets have been detected in the Alpha Centauri system. It is not an easy task to find a planet in a binary star system as the light wobbles about too much.
“Finding the wobble from a planet in a stellar spectrum is hard enough without having another star orbiting the one you are looking at,” says an astrologist. Researchers, though, are determined to look for planets in binary star systems and have planned to use other detection methods as well taking into account the patterns of periodic dimming and brightening of stars. Will these so-called eclipses and other methods help planet hunters discover the first Tatooine? Only time will tell.
Like our own Sun
A team from the California Institute of Technology, headed by Dr Charles Beichman, has succeeded in finding a star which resembles our Sun. By using the Nasa’s Spitzer Space Telescope, the team discovered an asteroid belt enveloping a star that is the same age and size of our Sun.
If the news is correct then we have discovered a star system much like our own, which is a rare finding indeed! Approximately 41 light years away, the star HD 69830 is composed of various minerals similar to the ones present in comet Hale-Bopp. Some of these are also found on other comets and asteroids, including Earth.
According to sci-fi writers Larry Niven and Jerry Pournelle, it is possible that other stars also have asteroid belts around them. In their novel, The mote in God’s eye, an alien civilization that had expanded and colonized space moved asteroids near a large gas giant. By moving these asteroids and positioning them at “Trojan” points around the planet, (sixty degrees ahead and sixty degrees behind), a stable equilibrium was created which resulted in the accumulation of space debris.
Coming back to binary systems, Dr Beichman and his team assumed that a giant comet, the size of Pluto, skidded into the system and is slowly spewing out the dust and debris. “The super comet theory is a long shot, but we’ll know soon enough,” says Beichman. Further observations will help astronomers confirm whether the comets and asteroids are producing the dust.
The bullied sun
Adding to the baffling mysteries of the cosmos, researchers have come across yet another strange phenomenon. In this case, instead of the Sun being the celestial body being orbited by a planet, this particular star is being bullied to gravitationally rotate in step with its planet.
The star is 1.4 times the mass of our Sun but tidally locked by a smaller celestial body — a most unusual scenario. The star Bootis is 50 light years away and is tidally locked by the rotation of a planet that encircles it in a tight 3.3-day orbit.
“This is truly a story of ‘tail wagging the dog,” says Jaymie Mathews from the University of British Columbia who is also the principal investigator at the Canadian Space Agency. “The interaction between the star and the giant planet in the tau Bootis system is unlike anything astronomers have seen before. And they would be undetectable by any instrument on Earth or in space other than Most (telescope),” he adds.
Most was launched in June of 2003 and is Canada’s only space telescope and weighs only 132 pounds. Detecting reflected light that comes off a planet, it gives clues to astronomers regarding the chemical composition of a planet and also whether it has clouds. Calculations revealed that the synchronization of the tau Bootis system might have taken a billion years.
Hence, as scientists and astronomers explore the universe a little more each day, they have to take a step back to marvel at the mysteries of the cosmos.
The writer is a freelance contributor
|
|
|
|
