habitable exoplanets Archives

September 28, 2023September 28, 2023 by Matt Williams

If Earth is Average, We Should Find Extraterrestrial Life Within 60 Light-Years

Illustration: Assortment of exoplanets — Astronomers have detected thousands of planets, including dozens that are potentially habitable. (NASA Illustration)

In 1960, while preparing for the first meeting on the Search for Extraterrestrial Intelligence (SETI), legendary astronomer and SETI pioneer Dr. Frank Drake unveiled his probabilistic equation for estimating the number of possible civilizations in our galaxy – aka. The Drake Equation. A key parameter in this equation was n_e, the number of planets in our galaxy capable of supporting life – aka. “habitable.” At the time, astronomers were not yet certain other stars had systems of planets. But thanks to missions like Kepler, 5523 exoplanets have been confirmed, and another 9,867 await confirmation!

Based on this data, astronomers have produced various estimates for the number of habitable planets in our galaxy – at least 100 billion, according to one estimate! In a recent study, Professor Piero Madau introduced a mathematical framework for calculating the population of habitable planets within 100 parsecs (326 light-years) of our Sun. Assuming Earth and the Solar System are representative of the norm, Madau calculated that this volume of space could contain as much as 11,000 Earth-sized terrestrial (aka. rocky) exoplanets that orbit within their stars’ habitable zones (HZs).

March 19, 2022March 19, 2022 by Matt Williams

Machine Learning Will be one of the Best Ways to Identify Habitable Exoplanets

Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. Scientists could use this one or one like it to measure planetary entropy production as a prelude to exploration. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)

The field of extrasolar planet studies is undergoing a seismic shift. To date, 4,940 exoplanets have been confirmed in 3,711 planetary systems, with another 8,709 candidates awaiting confirmation. With so many planets available for study and improvements in telescope sensitivity and data analysis, the focus is transitioning from discovery to characterization. Instead of simply looking for more planets, astrobiologists will examine “potentially-habitable” worlds for potential “biosignatures.”

This refers to the chemical signatures associated with life and biological processes, one of the most important of which is water. As the only known solvent that life (as we know it) cannot exist, water is considered the divining rod for finding life. In a recent study, astrophysicists Dang Pham and Lisa Kaltenegger explain how future surveys (when combined with machine learning) could discern the presence of water, snow, and clouds on distant 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.

November 15, 2020November 15, 2020 by Matt Williams

What Role do Radioactive Elements Play in a Planet’s Habitability?

To date, astronomers have confirmed the existence of 4,301 extrasolar planets in 3,192 star systems, with another 5,650 candidates awaiting confirmation. In the coming years, next-generation telescopes will allow astronomers to directly observe many of these exoplanets and place tighter constraints on their potential habitability. In time, this could lead to the discovery of life beyond our Solar System!

The only problem is, finding evidence of life requires that we know what to look for. According to a new study by an interdisciplinary team of scientists from the University of California Santa Cruz (UCSC), radioactive elements might play a role in planetary habitability. Future studies of rocky exoplanets, they argue, should therefore look for specific isotopes that indicate the presence of long-lived elements like thorium and uranium.

August 4, 2020August 4, 2020 by Matt Williams

Some Stars Could Support as Many as 7 Habitable Planets

Most exoplanets orbit red dwarf stars because they're the most plentiful stars. This is an artist's illustration of what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credits: NASA/JPL-Caltech

In recent decades, over 4,000 extrasolar planets have been confirmed beyond our Solar System. With so many planets available for study, astronomers have learned a great deal about the types of planets that exist out there and what kind of conditions are prevalent. For instance, they have been able to get a better idea of just how common habitable planets are (at least by our standards).

As it turns out, a surprisingly high number of planets out there could support life. That is the conclusion reached by a team of astronomers and planetary scientists who conducted a study of the possible sizes of habitable zones (HZ) based on stellar classification. After considering many planets could stably orbit within them, they came to the conclusion that stars with no Jupiter-sized gas giants can have as many as seven habitable planets!

July 16, 2020July 21, 2020 by Matt Williams

Do the TRAPPIST-1 Planets Have Atmospheres?

In February of 2017, the scientific community rejoiced as NASA announced that a nearby star (TRAPPIST-1) had a system of no less than seven rocky planets! Since that time, astronomers have conducted all kinds of follow-up observations and studies in the hopes of learning more about these exoplanets. In particular, they have been attempting to learn if any of the planets located in the stars Habitable Zone (HZ) could actually be habitable.

Many of these studies have been concerned with whether or not the TRAPPIST-1 planets have sufficient water on their surfaces. But just as important is the question of whether or not any have viable atmospheres. In a recent study that provides an overview of all observations to date on TRAPPIST-1 planets, a team found that depending on the planet in question, they are likely to have good atmospheres, if any at all.