Habitability Archives

January 17, 2023January 17, 2023 by Evan Gough

Worlds Bustling With Plantlife Should Shine in a Detectable Wavelength of Infrared

Artist's rendering of a super-Earth-type exoplanet, TOI 1452 b. Credit: Benoit Gougeon, Université de Montréal.

Future historians might look back on this time and call it the ‘exoplanet age.’ We’ve found over 5,000 exoplanets, and we’ll keep finding more. Next, we’ll move beyond just finding them, and we’ll turn our efforts to finding biosignatures, the special chemical fingerprints that living processes imprint on exoplanet atmospheres.

But there’s more to biosignatures than atmospheric chemistry. On a planet with lots of plant life, light can be a biosignature, too.

January 13, 2023January 11, 2023 by Paul M. Sutter

How Life Reshapes the Habitable Zone

An artist's impression of a warm, wet early Mars. Image Credit: Daein Ballard. CC-BY-SA-3.0

Astronomers are very interested in the Habitable Zone of distant stars, which is the orbital radius where liquid water, and therefore potentially life, can exist on a planet in that region. But life itself changes the characteristics of a planet. New research suggestions that life is even capable of redefining what the Habitable Zone can mean.

January 13, 2023January 13, 2023 by Evan Gough

TESS has Found A Second Earth-Sized World in This System. Exoplanet Science is Maturing

Newly discovered Earth-size planet TOI 700 e orbits within the habitable zone of its star in this illustration. Its Earth-size sibling, TOI 700 d, can be seen in the distance. Credit: NASA/JPL-Caltech/Robert Hurt

For planet-hunters, finding an Earth-sized exoplanet must be special. NASA estimates there are about 100 billion planets in the Milky Way, but the large majority of the 5,000+ exoplanets we’ve found are extremely inhospitable. So finding one that’s similar to ours is kind of comforting.

In this case, it’s even more interesting because it’s the second Earth-sized planet orbiting the same star.

December 16, 2022December 16, 2022 by Evan Gough

Are Planets Tidally Locked to Red Dwarfs Habitable? It’s Complicated

habitable exoplanet interstellar message — Artist's impression of a habitable exoplanet orbiting a red dwarf star. The habitability of the planets of red dwarf stars is conjectural (Credit ESO/M. Kornmesser public domain)

Astronomers are keenly interested in red dwarfs and the planets that orbit them. Up to 85% of the stars in the Milky Way could be red dwarfs, and 40% of them might host Earth-like exoplanets in their habitable zones, according to some research.

But there are some problems with their potential habitability. One of those problems is tidal locking.

December 14, 2022December 14, 2022 by Evan Gough

Could Life Survive on Frigid Exo-Earths? Maybe Under Ice Sheets

This artist's illustration shows what an icy exo-Earth might look like. A new study says liquid water could persist under ice sheets on planets outside of their habitable zones. Image Credit: NASA

Our understanding of habitability relies entirely on the availability of liquid water. All life on Earth needs it, and there’s every indication that life elsewhere needs it, too.

Can planets with frozen surfaces somehow have enough water to sustain life?

December 8, 2022December 8, 2022 by Evan Gough

Astronomers Have Found Two Temperate Super-Earths Orbiting a Nearby Red Dwarf

The telescopes of the SPECULOOS Southern Observatory gaze out into the stunning night sky over the Atacama Desert, Chile. ©ESO/P.Holárek

A team of astronomers has found two Super-Earths orbiting a red dwarf about 114 light-years away. The star, named LP 890-9, is the second coolest star found that hosts planets. Both the planets are likely temperate, and one of them “… is the second-most favourable habitable-zone terrestrial planet known so far,” according to the paper presenting the results.

November 24, 2022November 24, 2022 by Evan Gough

What’s the Best Mix of Oceans to Land for a Habitable Planet?

A new study asks what ratio of land to ocean is best for habitability? Image Credit: Reto Stöckli, Render by Robert Simmon. Based on data from the MODIS Science Team

Earth is about 29% land and 71% oceans. How significant is that mix for habitability? What does it tell us about exoplanet habitability?

October 20, 2022October 20, 2022 by Nancy Atkinson

Curiosity Arrives in a Salty Region of Mars. Was it Left Over From a Dying Sea?

A Mastcam image from the Mars Science Laboratory Curiosity rover on Sol 3609 of its mission. Credit: NASA/JPL-Caltech/MSSS/Kevin M. Gill.

The Curiosity rover has now reached its primary target on Mount Sharp on Mars, the mountain in the middle of Gale Crater the rover has been climbing since 2014. This target is not the summit, but a region over 600 meters (2,000 feet) up the mountain that planetary geologists have long anticipated reaching.

Known as the “sulfate-bearing unit,” the region is a boundary between the rocks that saw a lot of water in their history and those that didn’t; a possible shoreline, if you will. That boundary is already providing insights into Mars’ transition from a wet planet to dry, filling in a key gap in the understanding of the planet’s history.

June 28, 2022June 28, 2022 by Evan Gough

Water Worlds Could Have Plumes of Nutrients Carried up From Down Below

This reprocessed colour view of Jupiter’s moon Europa was made from images taken by NASA's Galileo spacecraft in the late 1990s. Credit: NASA/JPL-Caltech

Earth’s oceans are one huge, uniform electrolyte solution. They contain salt (sodium chloride) and other nutrients like magnesium, sulphate, and calcium. We can’t survive without electrolytes, and life on Earth might look very different without the oceans’ electrolyte content. It might even be non-existent.

On Earth, electrolytes are released into the oceans from rock by different processes like volcanism and hydrothermal activity.

Are these life-enabling nutrients available on water worlds?

May 11, 2022May 11, 2022 by Evan Gough

These are the Best Places to Search for Habitable Exomoons

An artist's conception of a potentially-habitable exomoon. Credit: NASA

Our Solar System contains eight planets and more than 200 moons. The large majority of those moons have no chance of being habitable, but some of them—Europa and Enceladus, for example—are strong candidates in the search for life.

Is it the same in other solar systems?