Mayank Chhaya-
The search for extraterrestrial life enters a dramatic new phase this month with NASA’s largest and most complex observatory James Webb Space Telescope now set to send the first full-color images and spectroscopic data on July 12.
The James Webb, which is a million miles from Earth and has its own orbit around the sun, has completed a six-month period of preparation before it could begin science work, calibrating its instruments to its space environment and aligning its mirrors. “This careful process, not to mention years of new technology development and mission planning, has built up to the first images and data: a demonstration of Webb at its full power, ready to begin its science mission and unfold the infrared universe,” NASA had said on June 1, 2022.
“As we near the end of preparing the observatory for science, we are on the precipice of an incredibly exciting period of discovery about our universe. The release of Webb’s first full-color images will offer a unique moment for us all to stop and marvel at a view humanity has never seen before,” Eric Smith, Webb program scientist at NASA Headquarters in Washington, had said then. “These images will be the culmination of decades of dedication, talent, and dreams – but they will also be just the beginning.”
Several teams will use the telescope, launched last Christmas, to explore various themes, one of which is to look for alien life. In particular, a group of teams will study the TRAPPIST star system where Seven Earth-sized planets were first observed by NASA’s Spitzer Space Telescope in February 2017, around a tiny, nearby, ultra-cool dwarf star called TRAPPIST-1. Three of these planets are firmly in the habitable zone, an area around a star where life has its most promising prospects to develop. It is known as the Goldilocks zone.
Earlier observations had suggested that three of the seven exoplanets are in the habitable zone.
As the search for habitable planets go, the TRAPPIST find is easily the most dramatic so far and likely to remain so for the foreseeable future. Scientists feel exhilarated if they find one possibly habitable exoplanet like they did in 2016 near in Proxima b orbiting Proxima Centauri star, the star closest to ours at barely four light years away.
While work is going on to study that candidate, the discovery of the TRAPPIST system upended all previous ones because of its sheer scale. The TRAPPIST 1 dwarf is so cool, according to NASA that most , if not all of the seven planets could possibly harbor surface water. That all seven are rocky is said to be a distinct possibility because of their densities.
The discovery of all seven by NASA’s Spitzer Space Telescope came after three of them were discovered in May 2016 using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. “Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. In the fall of 2016, Spitzer observed TRAPPIST-1 nearly continuously for 500 hours. Spitzer is uniquely positioned in its orbit to observe enough crossing – transits – of the planets in front of the host star to reveal the complex architecture of the system. Engineers optimized Spitzer’s ability to observe transiting planets during Spitzer’s “warm mission,” which began after the spacecraft’s coolant ran out as planned after the first five years of operations,” NASA had then said.
However, with the operationalization of the James Webb, the TRAPPIST system is expected to draw much more intense earthly attention for quite some time.
All seven TRAPPIST exoplanets may be tidally-locked, which means that only one of their hemispheres is exposed to their sun. Temperature variations between the hemispheres permanently exposed to their sun and permanently looking away could be extreme. Normally tidally-locked planets, even in the habitable zone, are considered inhospitable to life. However, if a dwarf could have seven planets, it is equally possible that some of them may actually have some form of life.
Scientists say of the three in the habitable zone the planet fifth from its star could be the likeliest candidate for life. Right now called just F it takes only 9.21 days to orbit the dwarf. Since it is tidally locked, its day and year would be of the same duration.
A striking feature of the TRAPPIST system is that since the planets are so close to one another, the view of the night sky on the surface of any of the seven would be extraordinary. “The (TRAPPIST-1) planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky,” NASA says.
The existence of exoplanets is relatively new knowledge first spotted in 1995 by French astronomers. It was called as 51 Pegasi b, orbiting around a sunlike star 50 light-years from Earth. According to NASA, the giant planet is about half the size of Jupiter and orbits its star every four days. With temperatures ranging between 1000 degrees F. and 1800 degrees F. it is considered inhospitable to life.
In the last 27 years since 51 Pegasi b since, scientists have found more than 5,000 other exoplanets.
Looking for alien life is only one of the missions James Webb but a major one.
