biosignatures Archives

April 22, 2024April 22, 2024 by Matt Williams

Will We Know if TRAPPIST-1e has Life?

Artist's impression of the Archean Eon. Credit: Tim Bertelink/Wikimedia

The search for extrasolar planets is currently undergoing a seismic shift. With the deployment of the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS), scientists discovered thousands of exoplanets, most of which were detected and confirmed using indirect methods. But in more recent years, and with the launch of the James Webb Space Telescope (JWST), the field has been transitioning toward one of characterization. In this process, scientists rely on emission spectra from exoplanet atmospheres to search for the chemical signatures we associate with life (biosignatures).

However, there’s some controversy regarding the kinds of signatures scientists should look for. Essentially, astrobiology uses life on Earth as a template when searching for indications of extraterrestrial life, much like how exoplanet hunters use Earth as a standard for measuring “habitability.” But as many scientists have pointed out, life on Earth and its natural environment have evolved considerably over time. In a recent paper, an international team demonstrated how astrobiologists could look for life on TRAPPIST-1e based on what existed on Earth billions of years ago.

March 5, 2024March 5, 2024 by Evan Gough

The LIFE Telescope Passed its First Test: It Detected Biosignatures on Earth.

LIFE will have five separate space telescopes that fly in formation and work together to detect biosignatures in exoplanet atmospheres. Image Credit: LIFE, ETH Zurich

We know that there are thousands of exoplanets out there, with many millions more waiting to be discovered. But the vast majority of exoplanets are simply uninhabitable. For the few that may be habitable, we can only determine if they are by examining their atmospheres. LIFE, the Large Interferometer for Exoplanets, can help.

February 26, 2024February 26, 2024 by Evan Gough

If Exoplanets Have Lightning, it’ll Complicate the Search for Life

Lightning on exoplanets could mask some biosignatures and amplify others. Image Credit: NASA/T.Pyle

Discovering exoplanets is almost routine now. We’ve found over 5,500 exoplanets, and the next step is to study their atmospheres and look for biosignatures. The James Webb Space Telescope is leading the way in that effort. But in some exoplanet atmospheres, lightning could make the JWST’s job more difficult by obscuring some potential biosignatures while amplifying others.

January 23, 2024January 23, 2024 by Brian Koberlein

What Could the Extremely Large Telescope See at Proxima Centauri's Planet?

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

Proxima Centauri B is the closest exoplanet to Earth. It is an Earth-mass world right in the habitable zone of a red dwarf star just 4 light-years from Earth. It receives about 65% of the energy Earth gets from the Sun, and depending on its evolutionary history could have oceans of water and an atmosphere rich with oxygen. Our closest neighbor could harbor life, or it could be a dry rock, but is an excellent target in the search for alien life. There’s just one catch. Our usual methods for detecting biosignatures won’t work with Proxima Centauri B.

January 21, 2024January 21, 2024 by Brian Koberlein

The Next Generation LIFE Telescope Could Detect Some Intriguing Biosignatures

Artist's impression of the proposed LIFE mission. Credit: LIFE Initiative / ETH Zurich

The Large Interferometer for Exoplanets (LIFE) project is an ambitious plan to build a space telescope with four independent mirrors. The array would allow the individual mirrors to move closer or farther apart, similar to the way the Very Large Array (VLA) does with radio antennas. LIFE is still early in its planning stage, so it would likely be decades before it is built, but already the LIFE team is looking at ways it might discover life on other worlds. Much of this focuses on the detection of biogenic molecules in exoplanet atmospheres.

November 19, 2023November 19, 2023 by Matt Williams

NASA Tests a Prototype Europa Lander

Testing Hardware for Potential Future Landing on Europa. Credit: NASA JPL-Caltech

In 2024, NASA will launch the Europa Clipper, the long-awaited orbiter mission that will fly to Jupiter (arriving in 2030) to explore its icy moon Europa. Through a series of flybys, the Clipper will survey Europa’s surface and plume activity in the hopes of spotting organic molecules and other potential indications of life (“biosignatures”). If all goes well, NASA plans to send a follow-up mission to land on the surface and examine Europa’s icy sheet and plumes more closely. This proposed mission is aptly named the Europa Lander.

While no date has been set, and the mission is still in the research phase, some significant steps have been taken to get the Europa Lander to the development phase. This past August, engineers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California tested a prototype of this proposed landing system in a simulated environment. This system combines hardware used by previous NASA lander missions and some new elements that will enable a mission to Europa. It also could be adapted to facilitate missions to more “Ocean Worlds” and other celestial bodies in our Solar System.

November 7, 2023November 7, 2023 by Evan Gough

Enceladus has All the Raw Materials for Life

Saturn's moon Enceladus isn't just bright and beautiful. It has an ocean under all that ice that could have hydrothermal vents that create organic chemicals. Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

Saturn’s ocean moon, Enceladus, is attracting increasing attention in the search for life in our Solar System. Most of what we know about Enceladus and its ice-covered ocean comes from the Cassini mission. Cassini ended its exploration of the Saturn system in 2017, but scientists are still working through its data.

New research based on Cassini data strengthens the idea that Enceladus has the chemicals necessary for life.

September 14, 2023September 14, 2023 by Evan Gough

Mini-Subs Could One Day Ply the Seas Under Europa’s Ice

This is a model of the miniature underwater vehicle being developed at MARUM with partners from industry. It will have a diameter of around ten cm and a length of about 50 cm. The tiny submarines will be placed inside a melt probe then released in the subglacial lakes under Antarctica. Image Credit: MARUM – Center for Marine Environmental Sciences, University of Bremen.

The most promising places to look for life in the Solar System are in the ocean moons Europa and Enceladus. But all that warm, salty, potentially life-supporting water is under thick sheets of ice: up to 30 km thick on Europa and up to 40 km thick for Enceladus.

The main obstacles to exploring all that water are the thick ice barriers. Assuming a spacecraft can be designed and built to melt its way through all that ice, what then?

Submarines can do the actual exploring, and they needn’t be large.

September 13, 2023September 13, 2023 by Brian Koberlein

Has the First Biosignature Been Found on an Exoplanet?

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov — Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Recently I wrote about the discovery of a hycean world. A potentially habitable exoplanet with a deep warm ocean and thick, hydrogen-rich atmosphere. Such planets are thought to be somewhat common orbiting red dwarf stars, and they are an excellent candidate for life. While it’s an exciting discovery, buried in the research article was something even more exciting. Tentative evidence of a biosignature, hinting at the presence of life. You can guess which discovery started making headlines. But have astronomers really found life on another planet?

August 22, 2023August 22, 2023 by Matt Williams

The Most Compelling Places to Search for Life Will Look Like “Anomalies”

Will it be possible someday for astrobiologists to search for life "as we don't know it"? Credit: NASA/Jenny Mottar

In the past two and a half years, two next-generation telescopes have been sent to space: NASA’s James Webb Space Telescope (JWST) and the ESA’s Euclid Observatory. Before the decade is over, they will be joined by NASA’s Nancy Grace Roman Space Telescope (RST), Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), and the ESA’s PLAnetary Transits and Oscillations of stars (PLATO) and ARIEL telescopes. These observatories will rely on advanced optics and instruments to aid in the search and characterization of exoplanets with the ultimate goal of finding habitable planets.

Along with still operational missions, these observatories will gather massive volumes of high-resolution spectroscopic data. Sorting through this data will require cutting-edge machine-learning techniques to look for indications of life and biological processes (aka. biosignatures). In a recent paper, a team of scientists from the Institute for Fundamental Theory at the University of Florida (UF-IFL) recommended that future surveys use machine learning to look for anomalies in the spectra, which could reveal unusual chemical signatures and unknown biosignatures.