Thanks to NASA, the Search for Habitable Worlds Just Got Easier


New NASA research will make it easier to find the planets out there that can support life. Detailed in the The Astrophysical Journal, the new model can simulate atmospheric conditions in a more comprehensive way, taking circulation of the atmosphere and other factors into account.

The search for habitable planets requires detailed modeling. The scope of the universe is simply too vast for scientists to spend time searching planet-by-planet. Instead, they calculate factors that would allow a planet to support liquid water—a requirement to support life as we know it—using simulations. For instance, it has to be just far enough from its parent star that the atmosphere isn't so cold that bodies of water freeze, but not so hot that they evaporate.

When planets are losing their oceans due to evaporation, they enter what's called a "moist greenhouse" state as the water vapor rises into the stratosphere and the hydrogen atoms break apart from the oxygen atoms to escape into space, eventually resulting in the loss of the planet's oceans. The new research details how a star's radiation influences how the atmosphere of an exoplanet circulates and plays a role in creating that moist greenhouse state. 

Planets that orbit a low-mass star—the most common kind of star in our galaxy—would have to be closer to that star than the Earth is to the Sun in order to support life, since a low-mass star is cooler and dimmer. The gravity from such a close star would slow down the rotation of the planet, and it might even become locked, with one side perpetually facing the star and one side perpetually facing away. (It would be as if the Eastern Hemisphere were always light and the Western Hemisphere were always dark.)

In turn, the planet would form a thick layer of clouds on the perpetually sunny side. The near-infrared radiation from the star—and cooler stars emit more of this radiation than hotter ones do—interacts with the water vapor in the air and the droplets and ice crystals in the clouds to warm up the air, creating the moist greenhouse state.

The moist greenhouse state could happen even at temperatures as low as those found in the tropical regions of Earth because of that near-infrared radiation interaction, according to the new model, but the study found that in exoplanets close to their stars, the process happens gradually enough that they could remain habitable. This more nuanced model will help guide scientists in their search for habitable planets near low-mass stars.

"As long as we know the temperature of the star, we can estimate whether planets close to their stars have the potential to be in the moist greenhouse state," study co-author Anthony Del Genio explained in a NASA press release. "Current technology will be pushed to the limit to detect small amounts of water vapor in an exoplanet's atmosphere. If there is enough water to be detected, it probably means that planet is in the moist greenhouse state."

Wednesday’s Best Amazon Deals Include Computer Monitors, Plant-Based Protein Powder, and Blu-ray Sets

As a recurring feature, our team combs the web and shares some amazing Amazon deals we’ve turned up. Here’s what caught our eye today, December 2. Mental Floss has affiliate relationships with certain retailers, including Amazon, and may receive a small percentage of any sale. But we only get commission on items you buy and don’t return, so we’re only happy if you’re happy. Good luck deal hunting!

Don't Miss Saturn And Jupiter's Great Conjunction on the Winter Solstice

Paul Williams, Flickr // CC BY-ND 2.0
Paul Williams, Flickr // CC BY-ND 2.0

In 2020, skygazers were treated to meteor showers, a new comet, and a Halloween blue moon. One of the last major astronomical events of the year is set to fall on the night of the winter solstice. On December 21, look up to catch Saturn in conjunction with Jupiter.

What is the conjunction of Saturn and Jupiter?

In astronomy, a conjunction occurs when two planets appear exceptionally close in the night sky. Two of our solar system's gas giants will share a celestial "kiss" on the longest night of the year. The rare meeting of Saturn and Jupiter is known as the "great conjunction" by astronomers.

Though conjunctions between the planets are fairly common, Saturn and Jupiter only get together once in a generation. Their last conjunction happened 20 years ago in the year 2000. Even if you were around for the last one, 2020's planetary meet-up is worth catching. Saturn and Jupiter will come within 0.1° of each other, or about one-fifth the width of a full moon. The last time the two planets came that close was in 1653, and they won't match that proximity again until 2080.

How to see the conjunction of Saturn and Jupiter

Saturn and Jupiter have been inching closer throughout October and November. You can find them now by looking for Jupiter, currently the brightest planet in the night sky, right after sunset. Saturn will appear just east of Jupiter as a dimmer planet with a golden hue.

As autumn wanes, the two planets will gradually bridge the space between them until they reach conjunction on winter solstice. On Monday, December 21, the planets will be so close that they may form a coalescence. That happens when the light from two planets appear to shine as a single star. When that happens, the super-bright body will be easy to spot.