exoplanets Archives

September 21, 2024September 21, 2024 by Matt Williams

Advanced Civilizations Will Overheat Their Planets Within 1,000 Years

Global temperature increases over the past thirty years, visualized. Credit: NOAA/NCEI

Earth’s average global temperatures have been steadily increasing since the Industrial Revolution. According to the National Oceanic and Atmospheric Agency (NOAA), Earth has been heating up at a rate of 0.06 °C (0.11 °F) per decade since 1850 – or about 1.11 °C (2 °F) in total. Since 1982, the average annual increase has been 0.20 °C (0.36 °F) per decade, more than three times as fast. What’s more, this trend is projected to increase by between 1.5 and 2 °C (2.7 to 3.6 °F) by mid-century, possibly more! This is a direct consequence of burning fossil fuels, which has increased exponentially since the mid-19th century.

Depending on the extent of temperature increases, the impact on Earth’s habitability could be catastrophic. In a recent study, a team of scientists examined how temperature increases are a long-term issue facing advanced civilizations and not just a matter of fossil fuel consumption. As they argue, rising planetary temperatures could be an inevitable result of the exponential growth of energy consumption. Their findings could have serious implications for astrobiology and the Search for Extraterrestrial Intelligence (SETI).

September 19, 2024September 25, 2024 by Evan Gough

Plants Would Still Grow Well Under Alien Skies

This is an artist's illustration of the rocky super Earth HD 219134. It orbits a K-type star, a long-lived stable type of main sequence star. The light from K-type stars is different than the Sun's. Can Earth plants photosynthesize effectively near these stars? Image Credit: By NASA/JPL-Caltech - http://photojournal.jpl.nasa.gov/jpeg/PIA19833.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=41995148

Photosynthesis changed Earth in powerful ways. When photosynthetic organisms appeared, it led to the Great Oxygenation Event. That allowed multicellular life to evolve and resulted in the ozone layer. Life could venture onto land, protected from the Sun’s intense ultraviolet radiation.

But Earth’s photosynthetic organisms evolved under the Sun’s specific illumination. How would plants do under other stars?

September 17, 2024September 17, 2024 by Matt Williams

Astronomers Have Found a Star with a Hot Jupiter and a Cold Super Jupiter in Orbit

Artist's vision of a cold super-Jupiter in the HD 118203 system. It is an extremely massive gas planet orbiting its star in an orbit six times that of Earth. Credit: NCU/ Maciejewski, G. et al (2024)

Located in the constellation Ursa Major, roughly 300 light-years from Earth, is the Sun-like star HD 118203 (Liesma). In 2006, astronomers detected an exoplanet (HD 118203 b) similar in size and twice as massive as Jupiter that orbits very closely to Liesma (7% of the distance between Earth and the Sun), making it a “Hot Jupiter.” In a recent study, an international team of astronomers announced the detection of a second exoplanet in this system: a Super Jupiter with a wide orbit around its star. In short, they discovered a “Cold Super-Jupiter” in the outskirts of this system.

September 12, 2024September 12, 2024 by Laurence Tognetti

Artemis Missions Could Put the most Powerful imaging Telescope on the Moon

Simulations depicting the potential solar physics science that the Artemis-enabled Stellar Imager (AeSI) on the Moon could accomplish. (Credit: Figure 2/Rau et al. (2024))

Ground-based interferometry on Earth has proven to be a successful method for conducting science by combining light from several telescopes into acting like a single large telescope. But how can a ultraviolet (UV)/optical interferometer telescope on the Moon deliver enhanced science, and can the Artemis missions help make this a reality? This is what a recently submitted study to the SPIE Astronomical Telescopes + Instrumentation 2024 conference hopes to address as a team of researchers propose the Artemis-enabled Stellar Imager (AeSI) that, as its name implies, could potentially be delivered to the lunar surface via NASA’s upcoming Artemis missions. This proposal was recently accepted as a Phase 1 study through NASA’s Innovative Advanced Concepts (NIAC) program and holds the potential to develop revolutionary extremely high-angular resolution way of conducting science on other planetary bodies while contributing to other missions, as well.

September 12, 2024September 12, 2024 by David Dickinson

Book Review: Is Earth Exceptional?

A new book looks at the latest scientific insights versus a key question in astronomy and space science.

It’s tough to answer a scientific question, with a just data point of one. How special are we, and how common (or rare) is the story of how life arose on the Earth in the grander drama of the cosmos?

A new book out this week entitled Is Earth Exceptional? The Quest for Cosmic Life by Mario Livio and Jack Szostak looks at the scientific state of answering this key question. The book offers a sweeping view of the nascent science of astrobiology, a multi-disciplinary field melding biology, chemistry, astronomy and more.

September 8, 2024September 8, 2024 by Matt Williams

ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk

ALMA images reveal vast spiral arms in the AB Aurigae circumstellar disk (three rightmost panels), and counterparts observed with VLT/SPHERE (leftmost panel). Credit: ALMA (ESO/NAOJ/NSF NRAO), VLT/SPHERE (ESO), Speedie et al.

According to Nebula Theory, stars and their systems of planets form when a massive cloud of gas and dust (a nebula) undergoes gravitational collapse at the center, forming a new star. The remaining material from the nebula then forms a disk around the star from which planets, moons, and other bodies will eventually accrete (a protoplanetary disk). This is how Earth and the many bodies that make up the Solar System came together roughly 4.5 billion years ago, eventually settling into their current orbits (after a few migrations and collisions).

However, there is still debate regarding certain details of the planet formation process. On the one hand, there are those who subscribe to the traditional “bottom-up” model, where dust grains gradually collect into larger and larger conglomerations over tens of millions of years. Conversely, you have the “top-down” model, where circumstellar disk material in spiral arms fragments due to gravitational instability. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence of the “top-down” model when observing a protoplanetary disk over 500 light-years away.

August 19, 2024August 19, 2024 by Laurence Tognetti

Earth-like exoplanets might be in short supply for the Habitable Worlds Observatory

How common are Earth-like exoplanets—also called exo-Earths—and which exoplanetary systems should we target to find them? This is what a recently submitted study hopes to address as a team of researchers investigated potential targets for the planned Habitable Worlds Observatory (HWO), which was recommended during the Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020) and is slated to launch in the 2040s. Most notably, HWO will use the direct imaging method to identify exo-Earths, and this study holds the potential to create a more scientifically cost-effective approach for identifying and studying exoplanets.

August 11, 2024August 11, 2024 by Matt Williams

New Study Examines the Links Between Science Fiction and Astronomy

Dr. Kip Thorne made it clear that black is not the primary hue of Black Holes. His guidance offered to Nolan raised science fiction to a new level. Credit: Paramount Pictures/Warner Bros.

“Today’s science fiction is tomorrow’s science fact.” This quote, attributed to Isaac Asimov, captures science’s intricate relationship with science fiction. And it is hardly a one-way relationship. Whereas science fiction is constantly evolving to reflect new scientific discoveries and theories, science itself has a long history of drawing inspiration from the works of visionary authors, filmmakers, and popular culture. And in some cases, where scientists themselves were the visionaries (like Asimov himself), you had an instance of both!

The relationship between the two was the subject of a recent study by Samuel Boissier, a researcher with the Centre National de la Recherche Scientifique (CNRS) and the director of research at the Laboratoire d’astrophysique de Marseille (LAM). In an age when misinformation, “deepfakes,” and deliberate attempts to obscure scientific truths are at an all-time high, examining the interconnection between science, art, and science fiction is very important. According to Boissier, doing so offers people in the scientific community a way to engage with the public in a way that is relatable and accessible.

August 5, 2024August 5, 2024 by Matt Williams

Habitable Planet’s Orbiting Red Dwarf Suns Could at Risk from Far-Ultraviolet Radiation

Artist's depiction of red-dwarf-flare. Image credit: Casey Reed/NASA

The question of whether or not red dwarf stars can support habitable planets has been subject to debate for decades. With the explosion in exoplanet discoveries in the past two decades, the debate has become all the more significant. For starters, M-type (red dwarf) stars are the most common in the Universe, accounting for 75% of the stars in our galaxy. Additionally, exoplanet surveys indicate that red dwarfs are particularly good at forming Earth-like rocky planets that orbit within their circumsolar habitable zones (CHZs).

Unfortunately, a considerable body of research has shown that planets orbiting red dwarf suns would be subject to lots of flare activity – including some so powerful they’re known as “superflares.” In a recent study led by the University of Hawai’i, a team of astrophysicists revealed that red dwarf stars can produce stellar flares with significantly more far-ultraviolet radiation than previously expected. Their findings could have drastic implications for exoplanet studies and the search for extraterrestrial life on nearby rocky planets.

July 25, 2024July 25, 2024 by Matt Williams

Planetary Habitability Depends on its Star’s Magnetic Field

Earth's magnetosphere is the region defined by our planet's magnetic field. Image Credit: NASA

The extrasolar planet census recently passed a major milestone, with 5500 confirmed candidates in 4,243 solar systems. With so many exoplanets available for study, astronomers have learned a great deal about the types of planets that exist in our galaxy and have been rethinking several preconceived notions. These include the notion of “habitability” and whether Earth is the standard by which this should be measured – i.e., could there be “super habitable” exoplanets out there? – and the very concept of the circumsolar habitable zone (CHZ).

Traditionally, astronomers have defined habitable zones based on the type of star and the orbital distance where a planet would be warm enough to maintain liquid water on its surface. But in recent years, other factors have been considered, including the presence of planetary magnetic fields and whether they get enough ultraviolet light. In a recent study, a team from Rice University extended the definition of a CHZ to include a star’s magnetic field. Their findings could have significant implications in the search for life on other planets (aka. astrobiology).