For a long time, the hunt for alien life and habitable planets has been a thrill for astronomers. With the passage of time, this hunt has spread outside the solar system. The discovery of exoplanets i.e. planets orbiting a star rather than the Sun started in 1988 and since then approximately 3583 exoplanets have been discovered so far. Recently, the hunt for habitable exoplanets has led to the discovery of a cluster of seven worlds all approximately the size of Earth and orbiting a neighboring star. NASA just announced the discovery of seven exoplanets orbiting a star TRAPPIST-1 which is 40 light years( 235 trillion miles) away from the planet Earth.
TRAPPIST-1 stands for Transiting Planets and Planetesimals Small Telescope. It is an ultra-cool dwarf star that shines 200 times dimmer than our Sun. Scientists speculate salmon red color glow of TRAPPIST-1.
This is the first time in history that so many exoplanets are discovered orbiting around the same star. All the seven exoplanets discovered are very close to their star and have orbits in the range of 1.5 to 20 days. These exoplanets are approximately the size same as that of Earth. The estimated mass of these exoplanets depicts that they are rocky planets. Also, the star faces the exoplanets from one side always. This means that on one side of the planet these is always a day and on the other side it is always a night.
Another interesting fact about this discovery is that out of these seven exoplanets, six have the surface temperature ranging from 0 to 100 oC and three have watery oceans. This means that these exoplanets orbit in the habitable zone of the TRAPPIST-1 System. In scientific terms, a planet in the habitable zone has the right amount of liquid water and environmental conditions for the survival of a living organism.
NASA’s exoplanet-hunting Spitzer Space Telescope was used during the discovery of these exoplanets. This microscope operates at the infrared wavelength (glowing brightest from TRAPPIST-1). Through this microscope, the team of astronomers working on this project accurately measured the sizes of all the planets. Moreover, they also estimated the masses and densities of six out of the seven exoplanets using the Spitzer Telescope.
Facts about Spitzer: Launched in 2003, it slowly follows Earth’s orbit around the Sun and helps in making much more discoveries than expected. Its final phase will last until 2018.
What do the experts say?
British astronomer Dr. Chris Copperwheat, from Liverpool John Moores University, who co-led the international team, said:
“The discovery of multiple rocky planets with surface temperatures which allow for liquid water, make this amazing system an exciting future target in the search for life.”
The dwarf start Trappist can be another solar system discovered in the Milky Way. According to some of the space agencies, this is a record breaking discovery in the history of space sciences.
Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA Headquarters said:
“The discovery gives us a hint that finding a second Earth is not just a matter of if, but when”. According to him, this is a major step forward in the discovery of “other worlds” in the universe.
The Trappist-1 planets make the search for life in the galaxy imminent,” said Sara Seager, an astronomer at the Massachusetts Institute of Technology who was not a member of the research team. “For the first time ever, we don’t have to speculate. We just have to wait and then make very careful observations and see what is in the atmospheres of the Trappist planets.
Dr. Seth Shostak, an astronomer at Seti Institute in Mountain View, California, said:
“If you’re looking for complex biology — intelligent aliens that might take a long time to evolve from pond scum — older could be better.
It seems a good bet that the majority of clever beings populating the universe look up to see a dim, reddish sun hanging in their sky. And at least they wouldn’t have to worry about sunblock.”
The presence of the exoplanets in the habitable zone does not guarantee the presence of life on this newly discovered system. Scientists will have to examine the atmospheres of these planets in detail to draw any conclusion about the presence of life on these exoplanets. For this purpose, scientists are using Hubble telescope and the James Webb Space Telescope will also join in next year to search for oxygen, ozone, and methane on these exoplanets. The presence of these gasses will confirm the presence of alien life of these exoplanets as these gasses are the byproducts of life. Scientists are estimating a time span of at least five years to figure out the atmosphere of these exoplanets and confirm the presence of life after it. David Charbonneau, a professor of astronomy at Harvard University said:
“This means we might be in the business of looking for aliens in a decade, and not, as others have envisioned, on a much longer timescale”.
NASA is so excited about the discovery that it has designed a “travel poster” for the TRAPPIST-1 system.