It’s the question on the minds of many: are there worlds similar to Earth in our galaxy?
A new model, with ties to Florida Tech, may provide clearer answers to a mystery faced by astrophysicts: Why it is that some planets around a certain type of star have not proved promising for life?
In March 2023, NASA scientists awaited data from the James Webb Space Telescope on a planet known as TRAPPIST-1b − the inner most planet orbiting the star TRAPPIST-1, which is a red dwarf star a lot smaller than our sun. The star system had generated significant interest as scientists hoped to discover water on the surface of the inner planets, which contain a rocky surface and are far enough from the star to potentially support water.
The result wasn’t what was expected. TRAPPIST-1b showed hardly any evidence of an atmosphere or water. This left the question: What makes these planets either contain or lack water — or even the elements needed for potential life?
Howard Chen, assistant professor at Florida Tech College of Engineering and Science: Department of Aerospace, Physics and Space Sciences, has worked to solve this mystery. Recently published in The Astrophysical Journal Letters, his paper, titled “Born Dry or Born Wet? A Palette of Water Growth Histories in TRAPPIST-1 Analogs and Compact Planetary Systemsoutlines” outlines a model which could explain this finding.
Chen is the leading scientist of the project and author of the paper, which was published in the journal in September. Along with scientists from the Applied Physics Laboratory at John Hopkins and Harvard University, the team created a model which shows the possibility as to why scientists were unable to find water on these planets.
Turns out, it could come down to how these planets were formed.
With the launch of modern-day space telescopes, such as Spitzer, Kepler, Hubble, and NASA’s James Webb Space Telescope, the race has been on to find out about worlds beyond our solar system. While many of these worlds — known as exoplanets — have been discovered around other stars, it has proven difficult to find worlds featuring even a fraction of the ocean Earth has.
“You have astronomers who are using telescopes to see what’s out there. I come from a different perspective,” Chen is quoted in a September Florida Tech news article as saying. “I’m both trying to explain what we’re seeing while trying to make predictions about what we can’t.”
For context, TRAPPIST-1 lies approximately 40-light years from Earth, meaning it would take the light from the star 40 years to been seen by our telescopes. But in terms of a galactic scale, Chen said that’s a small distance.
“40 lights years — it sounds like a long way from us, but it’s actually quite close compared to many other systems that we have discovered,” Chen told FLORIDA TODAY.
Still, with that distance, it makes the star too dim to spot from Earth without powerful telescopes. As for location in the night sky, the star sits in the constellation of Aquarius.
To date, astronomers have discovered seven planets orbiting TRAPPIST-1 — all of which can fit into an orbit comparable in size of our sun to Mercury.
Astronomers use something called transmission spectrum, which looks at the wavelengths of light emitted from a planet, to determine the elements found in the atmosphere of that world.
“One of the reasons why they might not be getting water is because they don’t have any methods to scatter water rich asteroids to the inner regions of the planet,” said Chen. “That might be the cause for the dry atmospheres.”
So essentially, that woud mean the planet is almost “born dry.”
He mentioned that close to home, Earth got its atmosphere from water-carrying asteroid impacts early in its formation. This water was carried from the outer regions of the solar system.
Chen’s study leans towards the fact that the further the planet is from the star, the more likely it is to contain water — possibly even frozen water on the most outer planets.
But this isn’t the only factor. Even though smaller in size, TRAPPIST-1 is a lot more active than our sun, which Chen states can disrupt a planet’s atmosphere and even impact the possibility of life on those worlds.
Future Florida Tech students could be using models such as Chen’s to work on investigating the unknowns of our universe. The next area of interest for Chen is seeking planets around white dwarf stars using a similar model.
“White dwarfs (are) a lot dimmer, so you can see the planet a lot better,” said Chen. “So for planets around sun-like stars, the stars are very bright, so it’s hard to see the planet.”
In terms of future discoveries, Chen believes our telescopes will continue to get better.
“If you ask me whether we find life elsewhere, it’s going to be tough,” said Chen. “But finding the condition in which you have a planet that’s the same mass as the Earth, and composition is dominated by nitrogen, with traces of carbon dioxide, I think that’s actually what should be quite common.”
Brooke Edwards is a Space Reporter for Florida Today. Contact her at bedwards@floridatoday.com or on X: @brookeofstars.
This article originally appeared on Florida Today: Wet or dry? Study with ties to Florida Tech could explain what NASA telescopes cannot
Reporting by Brooke Edwards, Florida Today / Florida Today
USA TODAY Network via Reuters Connect
