On Wednesday, February 22, 2017, in a highly-anticipated press conference set to unveil a “discovery beyond our solar system,” NASA triumphantly announced their remarkable, groundbreaking new find: an entire new solar system filled with planets similar to Earth and could potentially support life. NASA had alluded to the event in a press release a few days earlier, promising a revelation of major information about exoplanets, or planets that orbit stars other than our sun.
Researchers revealed during the press conference (video on right) that they have made perhaps the most promising exoplanet discovery ever, finding seven planets that are in orbit around a relatively nearby star, TRAPPIST-1.
All of the planets were found using a method called “transit photometry”. That works by watching out for when a planet passes, or transits, in front of its host star – blocking out a small amount of light, allowing us to see the planet and learn about its size.
Scientists first found the star TRAPPIST-1 in 2010, after monitoring the smallest stars close to the Sun. Since then, they have been watching out for those transits – and after seeing 34 of them clearly, they proposed that they can be attributed to the seven new planets.
They then worked to understand the size and composition of each of the worlds. That work is still continuing, but the researchers believe that the planets have large oceans, are temperate and other conditions that could make way for alien life.
At least three of the seven planets qualify as being the “holy grail for planet-hunting astronomers,” appearing to satisfy many of the most important, fundamental requirements for life: they reside within the “temperate zone,” are not excessively cold or warm, and are about the same size as Earth. They are also capable of supporting oceans and could feature a rocky floor and water, another indication that life could flourish on them.
No other star system has ever been found to contain so many Earth-sized and rocky planets, especially ones that have such great potential to support alien life.
The researchers might soon be able to find evidence of life on the planets, they have said. British astronomer Dr. Chris Copperwheat, from Liverpool John Moores University, who was part of 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.”
Co-researcher Dr. Amaury Triaud, from the Institute of Astronomy in Cambridge, said:
“We hope we will know if there’s life there within the next decade.”
While not a great deal is known about the planets for now, scientists hope to do extra work to discover what is on them and how they are formed. Doing that could even provide “convincing” evidence of life – if scientists detect certain molecules in the atmosphere, they can be almost sure that aliens can be found there, even though the planets are about 39 light years away and the fact that humans are unlikely to get there any time soon.
With the limited information that is currently available, the researchers and NASA have put together a vision of what life might look like on those planets, if humans were able to reach them:
In total, there are seven planets in the newly discovered solar system, all of them roughly the same size as our own Earth. Each of them moves much closer to its sun, since their star is much darker than our Sun.
Dr. Michael Gillon, from the STAR Institute at the University of Liege in Belgium, remarked:
“This is an amazing planetary system – not only because we have found so many planets, but because they are all surprisingly similar in size to the Earth.”
If a person were on one of the planets, everything would look a lot darker than usual, the scientists said. The amount of light heading to your eye would be about 200 times less than you get from the sun, and would be comparable to what you can see at sunset.
Despite that relative darkness, everything would still feel warm, the researchers said. That’s because roughly the same amount of energy would be coming from the star as warms our Earth – but it does so infrared.
If a person on one of the planets, everything would look a lot darker than usual, the scientists said. The amount of light heading to your eye would be about 200 times less than you get from the sun, and would be comparable to what you can see at sunset.
Because the star is so dim in relative terms, all of the planets are warmed enough to sit in the temperate zone. That’s despite the fact that they are all so close to it – each of them sitting nearer to the star than Mercury, the planet in our solar system that orbits closest to the Sun.
“The spectacle would be beautiful,” said Dr. Amaury Triaud, one of the scientists involved in the discovery. “Every now and then you’d see another planet, about as big as another moon in the sky.”
The sun would look about 10 times bigger than our own does from Earth, despite the fact that it is in fact only 8 per cent as big, Dr. Triaud said. He elaborated that it would be a sort of salmon pink color, noting that the scientists initially thought it would be a deep reddish crimson but most of that red light would be infrared and so invisible.
Even if life isn’t ever found near TRAPPIST-1, it might eventually develop there. The star is relatively young – even when our own Sun has run out of fuel and our solar system is destroyed, the newly-discovered one will still be in its early infancy.
TRAPPIST-1 “burns hydrogen so slowly that it will live for another 10 trillion years – more than 700 times longer than the Universe has existed so far, which is arguably enough time for life to evolve”, wrote Ignas AG Snellen from the Leiden Observatory, in an accompanying article about the discovery.
The researchers hope that they can do more work to watch the planets and learn more about their character. They want to look in particular at the seventh, outermost planet because at the moment they are not sure how it interacts with the inner ones.
NASA’s Hubble Space Telescope is already being used to search for atmospheres around the planets. Future telescopes, including the the European Extremely Large Telescope and James Webb Space Telescope, may be powerful enough to detect markers of life such as oxygen in the atmospheres of exoplanets.
Using the Hubble Space Telescope, astronomers have conducted the first search for atmospheres around temperate, Earth-sized planets beyond our solar system and found indications that increase the chances of habitability on two exoplanets.
Specifically, they discovered that the exoplanets TRAPPIST-1b and TRAPPIST-1c (shown passing in front of their parent red dwarf star in image to the left), approximately 40 light-years away, are unlikely to have puffy, hydrogen-dominated atmospheres usually found on gaseous worlds. (Image Credits: NASA/ESA/STScI/J. de Wit (MIT))
“The lack of a smothering hydrogen-helium envelope increases the chances for habitability on these planets,” said team member Nikole Lewis of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “If they had a significant hydrogen-helium envelope, there is no chance that either one of them could potentially support life because the dense atmosphere would act like a greenhouse.”
Julien de Wit of the Massachusetts Institute of Technology in Cambridge, Massachusetts, led a team of scientists to observe the planets in near-infrared light using Hubble’s Wide Field Camera 3. They used spectroscopy to decode the light and reveal clues to the chemical makeup of an atmosphere. While the content of the atmospheres is unknown and will have to await further observations, the low concentration of hydrogen and helium has scientists excited about the implications.
“These initial Hubble observations are a promising first step in learning more about these nearby worlds, whether they could be rocky like Earth, and whether they could sustain life,” says Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “This is an exciting time for NASA and exoplanet research.”
The planets orbit a red dwarf star at least 500 million years old, in the constellation of Aquarius. They were discovered in late 2015 through a series of observations by the TRAnsiting Planets and PlanetesImals Small Telescope (TRAPPIST), a Belgian robotic telescope located at ESA’s (European Space Agency’s) La Silla Observatory in Chile.
TRAPPIST-1b completes a circuit around its red dwarf star in 1.5 days and TRAPPIST-1c in 2.4 days. The planets are between 20 and 100 times closer to their star than the Earth is to the sun. Because their star is so much fainter than our sun, researchers think that at least one of the planets, TRAPPIST-1c, may be within the star’s habitable zone, where moderate temperatures could allow for liquid water to pool.
The first exoplanet was found in 1992. Since then, astronomers have detected more than 3,500 of the worlds, distributed across 2,675 star systems.
About a fifth of the sun-like stars are thought to have Earth-sized planets close enough to them to support life.
In all, there might be 40 billion potentially habitable words sitting just in our galaxy, the Milky Way, astronomers estimate.
Scientists have long thought that Earth-sized planets were abundant, but the new research shows just how many of them there might be. Many of those planets might never be seen, because they don’t pass in front of their host star and so aren’t visible.
That might mean that the new system is actually not all that out of the ordinary. Scientists expect that for each planet we find, there are as many as 100 we can’t see – and so the scientists might not actually have been lucky, but rather seen something that wasn’t that unusual.
Expanded from original sources, whose authors retain all copyrights:
- “NASA Discovers Entire New Solar System: What Could Life There Look Like?” by Andrew Griffin, published at The UK Independent on February 22, 2017.
- “NASA’s ‘Holy Grail’: Entire New Solar System That Could Support Alien Life Discovered” by Andrew Griffin, published at The UK Independent on February 22, 2017.
- “NASA’s Hubble Telescope Makes First Atmospheric Study of Earth-Sized Exoplanets” published by NASA on July 20, 2016.