Habitability Archives

June 27, 2021June 29, 2021 by Matt Williams

Most Exoplanets won’t Receive Enough Radiation to Support an Earth-Like Biosphere

Earth as seen by the JUNO spacecraft in 2013. Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

To date, astronomers have confirmed the existence of 4,422 extrasolar planets in 3,280 star systems, with an additional 7,445 candidates awaiting confirmation. Of these, only a small fraction (165) have been terrestrial (aka. rocky) in nature and comparable in size to Earth – i.e., not “Super-Earths.” And even less have been found that are orbiting within their parent star’s circumsolar habitable zone (HZ).

In the coming years, this is likely to change when next-generation instruments (like James Webb) are able to observe smaller planets that orbit closer to their stars (which is where Earth-like planets are more likely to reside). However, according to a new study by researchers from the University of Napoli and the Italian National Institute of Astrophysics (INAF), Earth-like biospheres may be very rare for exoplanets.

June 18, 2021June 18, 2021 by Matt Williams

A New Technique for “Seeing” Exoplanet Surfaces Based on the Content of their Atmospheres

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 November of 2021, the James Webb Space Telescope (JWST) will make its long-awaited journey to space. This next-generation observatory will observe the cosmos using its advanced infrared suite and reveal many never-before-seen things. By 2024, it will be joined the Nancy Grace Roman Space Telescope (RST), the successor to the Hubble mission that will have 100 times Hubble’s field of view and faster observing time.

These instruments will make huge contributions to many fields of research, not the least of which is the discovery and characterization of extrasolar planets. But even with their advanced optics and capabilities, these missions will not be able to examine the surfaces of exoplanets in any detail. However, a team of the UC Santa Cruz (UCSC) and the Space Science Institute (SSI) have developed the next best thing: a tool for detecting an exoplanet surface without directly seeing it.

March 5, 2021October 29, 2021 by Matt Williams

How Would Rain be Different on an Alien World?

Artist’s impression of a sunset seen from the surface of an Earth-like exoplanet. Credit: ESO/L. Calçada

On Titan, Saturn’s largest moon, it rains on a regular basis. As with Earth, these rains are the result of liquid evaporating on the surface, condensing in the skies, and falling back to the surface as precipitation. On Earth, this is known as the hydrological (or water) cycle, which is an indispensable part of our climate. In Titan’s case, the same steps are all there, but it is methane that is being exchanged and not water.

In recent years, scientists have found evidence of similar patterns involving exoplanets, with everything from molten metal to lava rain! This raises the question of just how exotic the rains may be on alien worlds. Recently, a team of researchers from Havard University conducted a study where they researched how rain would differ in a diverse array of extrasolar planetary environments.

February 10, 2021February 10, 2021 by Matt Williams

Super-Earth Conditions Simulated in the Lab to Discover if They’re Habitable

An artist’s conception of the magnetic fields of selected super-Earths as the Z machine, pictured at bottom, mimics the gravitational conditions on other planets. Credits: Eric Lundin; Z photo by Randy Montoya

Deep inside planet Earth, there is a liquid outer core and a solid inner core that counter-rotate with each other. This creates the dynamo effect that is responsible for generating Earth’s planetary magnetic field. Also known as a magnetosphere, this field keeps our climate stable by preventing Earth’s atmosphere from being lost to space. So when studying rocky exoplanets, scientists naturally wonder if they too have magnetospheres.

Unfortunately, until we can measure an exoplanet’s magnetic fields, we are forced to infer their existence from the available evidence. This is precisely what researchers at the Sandia National Laboratories did with its Z Pulsed Power Facility (PPF). Along with their partners at the Carnegie Institution for Science, they were able to replicate the gravitational pressures of “Super-Earths” to see if they could generate magnetic fields.

October 25, 2020October 30, 2020 by Matthew Cimone

The Color of Habitable Worlds

An arrangement of 3 exoplanets to explore how the atmospheres can look different based on the chemistry present and incoming flux. - image and image description by Jack H. Madden used with permission

“This is where we live. On a Blue Dot.” said Carl Sagan when the now famous Pale Blue Dot photo was released. Captured February 14, 1990 by the Voyager 1 Space Probe, Pale Blue Dot remains the most distant photograph of the Earth ever taken at 6 billion kilometers. This past February marked the 30^th anniversary of Pale Blue Dot which was reprocessed using modern digital photo techniques creating an even more remarkable image.

This updated version of the iconic “Pale Blue Dot” image taken by the Voyager 1 spacecraft uses modern image-processing software and techniques to revisit the well-known Voyager view while attempting to respect the original data and intent of those who planned the images. Credit: NASA/JPL-Caltech

Whether Pale Blue Dot, or Blue Marble, our planet is associated with the color blue. As Earth is the only inhabited world we know of, it might stand to reason that other habitable planets in space will also be blue. But it’s a little more complicated than that.

October 13, 2020October 14, 2020 by Matthew Cimone

The Search for Superhabitable Planets. Worlds Even More Habitable Than Earth

Kepler-22b, seen in this artist's rendering, is a planet a bit larger than Earth that orbits in the habitable zone of its star. Some researchers think there might be "superhabitable" worlds that may not resemble Earth. c. NASA

REMINDER: – Universe Today will be hosting an interview with Dr. Dirk Schulze-Makuch, co-author of the research featured in this article, on Thursday October 15^th, 2020 at 8:30am PT. Click the video below to watch live or to see the recorded stream afterward

Out Earthing Earth

What planet is this?

If you said Hoth, that’s a good guess. But, it’s actually Earth depicted in one of two known “snowball” states. The entire planet’s surface was locked beneath glacial ice during the Cryogenian Period 650 million years ago and during the Huronian Glaciation 2 – 2.4 billion years ago.

October 9, 2020October 9, 2020 by Evan Gough

Just How Bad are Superflares to a Planet’s Habitability?

Star’s can be full of surprises; some of them nasty. While our own Sun appears pretty placid, science has shown us that’s not the case. Coronal mass ejections and solar flares are the Sun’s angry side.

And the Sun has only a mild case of the flares, compared to some other stars.

June 29, 2020June 29, 2020 by Evan Gough

More Evidence that Europa’s Oceans Could be Habitable

A "true color" image of the surface of Jupiter's moon Europa as seen by the Galileo spacecraft. In 2030, the Europa Clipper mission will start its close flybys of this ocean world. Image credit: NASA/JPL-Caltech/SETI Institute

At first glance, Jupiter’s moon Europa doesn’t seem much like Earth. It’s a moon, not a planet, and it’s covered in ice. But it does have one important thing in common with Earth: a warm, salty ocean.

Now there’s even more evidence that Europa’s sub-surface ocean is habitable.

June 19, 2020June 21, 2020 by Evan Gough

Astronomers Estimate There Are 6 Billion Earth-Like Planets in the Milky Way

Meet Kepler-22b, an exoplanet with an Earth-like radius in the habitable zone of its host star. Unfortunately its mass remains unknown. Image Credit: NASA

Six billion Earth-like planets in the Milky Way? If true, that’s astounding. But the number needs some context.

The Milky Way has up 400 billion stars. So even if there are six billion Earth-like planets, they’re still spread far and wide throughout our vast galaxy.

May 22, 2020May 22, 2020 by Evan Gough

Ocean Circulation Might Be the Key to Finding Habitable Exoplanets

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

We’ve found thousands and thousands of exoplanets now. And spacecraft like TESS will likely find thousands and thousands more of them. But most exoplanets are gassy giants, molten hell-holes, or frozen wastes. How can we find those needles-in-the-haystack habitable worlds that may be out there? How can we narrow our search?

Well, first of all, we need to find water. Oceans, preferably, since that’s where life began on Earth. And according to a new study, those oceans need to circulate in particular ways to support life.