Habitability Archives

April 2, 2020April 2, 2020 by Evan Gough

Astronomers Define the “Really Habitable Zone”. Planets Capable of Producing Gin and Tonic

Gin and tonic. Image Credit: By NotFromUtrecht - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8529628

A hospitable star that doesn’t kill you with deadly flares. A rocky planet with liquid water and an agreeable climate. Absence of apocalyptic asteroid storms. No pantheon of angry, vengeful, and capricious gods. These are the things that define a habitable planet.

Now some scientists are adding one more criterion to the list: gin and tonic.

March 27, 2020 by Matt Williams

How Will Clouds Obscure the View of Exoplanet Surfaces?

This artist’s impression shows the planet K2-18b, it’s host star and an accompanying planet in this system. K2-18b is now the only super-Earth exoplanet known to host both water and temperatures that could support life. UCL researchers used archive data from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b’s atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.

In 2021, NASA’s next-generation observatory, the James Webb Space Telescope (JWST), will take to space. Once operational, this flagship mission will pick up where other space telescopes – like Hubble, Kepler, and Spitzer – left off. This means that in addition to investigating some of the greatest cosmic mysteries, it will also search for potentially habitable exoplanets and attempt to characterize their atmospheres.

This is part of what sets the JWST apart from its predecessors. Between its high sensitivity and infrared imaging capabilities, it will be able to gather data on exoplanet atmospheres like never before. However, as a NASA-supported study recently showed, planets that have dense atmospheres might also have extensive cloud cover, which could complicate attempts to gather some of the most important data of all.

January 28, 2020November 10, 2021 by Matt Williams

Here’s What the Climate Might Look Like on Proxima Centauri B

Located at the heart of the NASA Center for Climate Simulation (NCCS) – part of NASA’s Goddard Space Flight Center – is the Discover supercomputer, a 129,000-core cluster of Linux-based processors. This supercomputer, which is capable of conducting 6.8 petaflops (6.8 trillion) operations per second, is tasked with running sophisticated climate models to predict what Earth’s climate will look like in the future.

However, the NCCS has also started to dedicate some of Discover’s supercomputing power to predict what conditions might be like on any of the over 4,000 planets that have been discovered beyond our Solar System. Not only have these simulations shown that many of these planets could be habitable, they are further evidence that our very notions of “habitability” could use a rethink.

January 10, 2020January 10, 2020 by Evan Gough

The Perfect Stars to Search for Life On Their Planets

This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G stars; stars less massive and cooler than our Sun are K dwarfs; and even fainter and cooler stars are the reddish M dwarfs. The graphic compares the stars in terms of several important variables. The habitable zones, potentially capable of hosting life-bearing planets, are wider for hotter stars. The longevity for red dwarf M stars can exceed 100 billion years. K dwarf ages can range from 15 to 45 billion years. And, our Sun only lasts for 10 billion years. The relative amount of harmful radiation (to life as we know it) that stars emit can be 80 to 500 times more intense for M dwarfs relative to our Sun, but only 5 to 25 times more intense for the orange K dwarfs. Red dwarfs make up the bulk of the Milky Way's population, about 73%. Sunlike stars are merely 6% of the population, and K dwarfs are at 13%. When these four variables are balanced, the most suitable stars for potentially hosting advanced life forms are K dwarfs. Credits: NASA, ESA and Z. Levy (STScI)

We tend to think of our Earthly circumstances as normal. A watery, temperate world orbiting a stable yellow star. A place where life has persisted for nearly 4 billion years. It’s almost inevitable that when we think of other places where life could thrive, we use our own experience as a benchmark.

But should we?

January 8, 2020January 8, 2020 by Evan Gough

TESS Finds its First Earth-Sized World in the Habitable Zone of a Star

An artist's illustration of TOI 700d, an Earth-size exoplanet that TESS found in its star's habitable zone. Image Credit: NASA

NASA’s TESS (Transiting Exoplanet Survey Satellite) has found its first Earth-sized planet located in the habitable zone of its host star. The find was confirmed with the Spitzer Space Telescope. This planet is one of only a few Earth-sized worlds ever found in a habitable zone.

December 19, 2019December 19, 2019 by Evan Gough

Without a Magnetosphere, Planets Orbiting Flare Stars Don’t Stand a Chance

An artist's conception of a superflare event, on a dwarf star. Image credit: Mark Garlick/University of Warwick

Earthlings are fortunate. Our planet has a robust magnetic shield. Without out magnetosphere, the Sun’s radiation would’ve probably ended life on Earth before it even got going. And our Sun is rather tame, in stellar terms.

What’s it like for exoplanets orbiting more active stars?

October 15, 2019October 15, 2019 by Evan Gough

Planet Sizes Matter for Habitability Too.

In order to be considered habitable, a planet needs to have liquid water. Cells, the smallest unit of life, need water to carry out their functions. For liquid water to exist, the temperature of the planet needs to be right. But how about the size of the planet?

Without sufficient mass a planet won’t have enough gravity to hold onto its water. A new study tries to understand how size affects the ability of a planet to hold onto its water, and as a result, its habitability.

September 21, 2019September 25, 2019 by Matt Williams

Venus Could Have Supported Life for Billions of Years

Artist's conception of a terraformed Venus, showing a surface largely covered in oceans. Credit: Wikipedia Commons/Ittiz

In 1978, NASA’s Pioneer Venus (aka. Pioneer 12) mission reached Venus (“Earth’s Sister”) and found indications that Venus may have once had oceans on its surface. Since then, several missions have been sent to Venus and gathered data on its surface and atmosphere. From this, a picture has emerged of how Venus made the transition from being an “Earth-like” planet to the hot and hellish place it is today.

It all started about 700 million years ago when a massive resurfacing event triggered a runaway Greenhouse Effect that caused Venus’s atmosphere to become incredibly dense and hot. This means that for 2 to 3 billion years after Venus formed, the planet could have maintained a habitable environment. According to a recent study, that would have been long enough for life to have emerged on “Earth’s Sister”.

July 31, 2019July 31, 2019 by Evan Gough

NASA Promised More Smaller, Earth-size Exoplanets. TESS is Delivering.

This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, calculated without the warming effects of any possible atmospheres. Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger

When NASA launched TESS (Transiting Exoplanet Survey Satellite) in 2018, it had a specific goal. While its predecessor, the Kepler spacecraft, found thousands of exoplanets, many of them were massive gas giants. TESS was sent into space with a promise: to find smaller planets similar in size to Earth and Neptune, orbiting stable stars without much flaring. Those constraints, astronomers hoped, would identify more exoplanets that are potentially habitable.

With this discovery of three new exoplanets, TESS is fulfilling its promise.

July 18, 2019July 18, 2019 by Evan Gough

Blankets of Silica Aerogel Could Make Parts of Mars Habitable

In Earth's atmosphere, CO2 lets sunlight in, but traps it in the atmosphere, warming the planet. The same thing, sort of, happens on Mars, where all the CO2 is frozen. Polar ice caps on Mars are a combination of water ice and frozen CO2. Just like its gaseous form here on Earth, frozen CO2 allows sunlight to penetrate while trapping heat. In the summer, this solid-state greenhouse effect creates pockets of warming under the ice, seen here as black dots in the ice. Image Credit: NASA

The idea of somehow terra-forming Mars to make it more habitable is a visionary, sci-fi dream. But though global terra-forming of Mars is out of reach, the idea persists. But now, a material called silica aerogel might make make the whole idea of terra-forming Mars slightly less impossible.