exoplanets Archives

April 23, 2024April 23, 2024 by Nancy Atkinson

Purple Bacteria — Not Green Plants — Might Be the Strongest Indication of Life

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

Astrobiologists continue to work towards determining which biosignatures might be best to look for when searching for life on other worlds. The most common idea has been to search for evidence of plants that use the green pigment chlorophyll, like we have on Earth. However, a new paper suggests that bacteria with purple pigments could flourish under a broader range of environments than their green cousins. That means current and next-generation telescopes should be looking for the emissions of purple lifeforms.

“Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,” said Lígia Fonseca Coelho, a postdoctoral associate at the Carl Sagan Institute (CSI) and first author of “Purple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds,” published in the Monthly Notices of the Royal Astronomical Society: Letters.

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.

April 9, 2024April 9, 2024 by Andy Tomaswick

The Seven Most Intriguing Worlds to Search for Advanced Civilizations (So Far)

Sometimes, the easy calculations are the most interesting. A recent paper from Balázs Bradák of Kobe University in Japan is a case in point. In it, he takes an admittedly simplistic approach but comes up with seven known exoplanets that could hold the key to the biggest question of them all – are we alone?

April 3, 2024April 3, 2024 by Andy Tomaswick

Could We Directly Observe Volcanoes on an Exoplanet?

After a few decades of simply finding exoplanets, humanity is starting to be able to do something more – peer into their atmospheres. The James Webb Space Telescope (JWST) has already started looking at the atmospheres of some larger exoplanets around brighter stars. But in many cases, scientists are still developing models that both explain what the planet’s atmosphere is made of and match the data. A new study from researchers at UC Riverside, NASA’s Goddard Spaceflight Center, American University, and the University of Maryland looks at what one particular atmospheric process might look like on an exoplanet – volcanism.

March 25, 2024March 25, 2024 by Evan Gough

Life Might Be Difficult to Find on a Single Planet But Obvious Across Many Worlds

This artist's illustration shows the exoplanet WASP-62B. Searching for chemical biosignatures on exoplanets is a painstaking process, weighed down by assumptions and prone to false positives. Is there a better way to find exoplanets with a chance to support life? Image Credit: CfA

If we could detect a clear, unambiguous biosignature on just one of the thousands of exoplanets we know of, it would be a huge, game-changing moment for humanity. But it’s extremely difficult. We simply aren’t in a place where we can be certain that what we’re detecting means what we think or even hope it does.

But what if we looked at many potential worlds at once?

March 9, 2024March 17, 2024 by Matt Williams

This Hot Jupiter is Doomed to Crash Into its Star in Just Three Million Years

Artist's impression of the searing-hot gas planet WASP-12b and its star. A Princeton-led team of astrophysicists has shown that this exoplanet is spiraling in toward its host star, heading toward certain destruction in about 3 million years. Credit: NASA/JPL-Caltech

In 2008, astronomers with the SuperWASP survey spotted WASP-12b as it transited in front of its star. At the time, it was part of a new class of exoplanets (“Hot Jupiters”) discovered a little more than a decade before. However, subsequent observations revealed that WASP-12b was the first Hot Jupiter observed that orbits so closely to its parent star that it has become deformed. While several plausible scenarios have been suggested to explain these observations, a widely accepted theory is that the planet is being pulled apart as it slowly falls into its star.

Based on the observed rate of “tidal decay,” astronomers estimate that WASP-12b will fall into its parent star in about ten million years. In a recent study, astronomers with The Asiago Search for Transit Timing Variations of Exoplanets (TASTE) project presented an analysis that combines new spectral data from the Telescopio Nazionale Galileo (TNG) in La Palma with 12 years worth of unpublished transit light curves and archival data. Their results are consistent with previous observations that suggest WASP-12b is rapidly undergoing tidal dissipation and will be consumed by its star.

March 8, 2024March 8, 2024 by Matt Williams

Science Fiction is Learning About Exoplanets From Science

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

As long as it has existed as a genre, there has been a notable relationship between science fiction and science fact. Since our awareness of the Universe and everything in it has changed with time, so have depictions and representations in popular culture. This includes everything from space exploration and extraterrestrial life to extraterrestrial environments. As scientists keep pushing the boundaries of what is known about the cosmos, their discoveries are being related to the public in film, television, print, and other media.

In the field of science communication, however, there is a certain hesitancy to use science fiction materials as an educational tool. In a recent paper that appeared in the Journal of Science Communication (JCOM), a team from the St Andrews Centre for Exoplanet Science and the Space Research Institute (IWF) of the Austrian Academy of Sciences focused on a specific area of scientific study – extrasolar planets. After analyzing a multimedia body of science fiction works produced since the first confirmed exoplanet discovery, they found that depictions have become more realistic over time.

March 4, 2024March 4, 2024 by Brian Koberlein

Astronomers Can See the Impact Site Where an Asteroid Crashed Into a White Dwarf

This artist’s impression shows the magnetic white dwarf WD 0816-310. Credit: ESO/L. Calçada

Nothing is immortal. Everything has a finite existence, including the stars themselves. How a star dies depends on several factors, most importantly their mass. For the Sun, this means that in several billion years it will swell to a red giant as it churns through the last of its nuclear fuel. The core that remains will then collapse to become a white dwarf. Of course, the Sun is home to several planets, including Earth. What of their fate? What of ours? According to a recent study, the Sun’s death might consume Earth in the end.

January 31, 2024January 31, 2024 by Matt Williams

Six Planets Found Orbiting an Extremely Young Star

Artist rendering of the TOI-1136 system and its young star flaring. Credit: Rae Holcomb/Paul Robertson/UCI

The field of exoplanet study continues to grow by leaps and bounds. As of the penning of this article, 5,572 extrasolar planets have been confirmed in 4,150 systems (with another 10,065 candidates awaiting confirmation. Well, buckle up because six more exoplanets have been confirmed around TOI-1136, a Sun-like star located roughly 276 light-years from Earth. This star is less than 700 million years old, making it relatively young compared to our own (4.6 billion years). This system will allow astronomers to observe how systems like our own have evolved with time.

January 30, 2024January 30, 2024 by Laurence Tognetti

Astrobiology: Why study it? How to study it? What are the challenges?

Universe Today has proudly examined the importance of studying impact craters, planetary surfaces, and exoplanets, and what they can teach scientists and the public about finding life beyond Earth. Impact craters both shape these planetary surfaces and hold the power to create or destroy life, and we learned how exoplanets are changing our views of planetary formation and evolution, including how and where we might find life in the cosmos. Here, we will discuss how these disciplines contribute to the field responsible for finding life beyond Earth, known as astrobiology. We will discuss why scientists study astrobiology, also known as astrobiologists, challenges of studying astrobiology, and how students can pursue studying astrobiology, as well. So, why is it so important to study astrobiology?