exoplanets Archives

January 14, 2024January 14, 2024 by Matt Williams

Since Interstellar Objects Crashed Into Earth in the Past, Could They Have Brought Life?

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

On October 19^th, 2017, astronomers with the Pan-STARRS survey detected an interstellar object (ISO) passing through our Solar System for the first time. The object, known as 1I/2017 U1 Oumuamua, stimulated significant scientific debate and is still controversial today. One thing that all could agree on was that the detection of this object indicated that ISOs regularly enter our Solar System. What’s more, subsequent research has revealed that, on occasion, some of these objects come to Earth as meteorites and impact the surface.

This raises a very important question: if ISOs have been coming to Earth for billions of years, could it be that they brought the ingredients for life with them? In a recent paper, a team of researchers considered the implications of ISOs being responsible for panspermia – the theory that the seeds of life exist throughout the Universe and are distributed by asteroids, comets, and other celestial objects. According to their results, ISOs can potentially seed hundreds of thousands (or possibly billions) of Earth-like planets throughout the Milky Way.

January 4, 2024January 4, 2024 by Nancy Atkinson

Astronomers Test an Exoplanet Instrument on Jupiter

NASA’s Juno spacecraft captured this view of Jupiter during the mission’s 40th close pass by the giant planet on Feb. 25, 2022. The large, dark shadow on the left side of the image was cast by Jupiter’s moon Ganymede. Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing by Thomas Thomopoulos

The European Southern Observatory’s Very Large Telescope (VLT) has a high-resolution spectrograph called ESPRESSO, designed specifically to detecting and characterize exoplanets. Astronomers recently ran a test with the instrument, studying the atmosphere and winds of Jupiter. They used a technique called Doppler velocimetry to measure the reflection of light from the Sun in the planet’s clouds, allowing for instantaneous measurement of the clouds’ wind speeds. The technique has also been used on Venus and will guide the future study of exoplanets.

January 2, 2024January 3, 2024 by Matt Williams

After all of This Time Searching for Aliens, is it The Zoo Hypothesis or Nothing?

The Karl Jansky Very Large Array at night, with the Milky Way visible in the sky. Credit: NRAO/AUI/NSF; J. Hellerman

In 1950, during a lunchtime conversation with colleagues at the Los Alamos National Laboratory, famed physicist Enrico Fermi asked the question that launched a hundred (or more) proposed resolutions. “Where is Everybody?” In short, given the age of the Universe (13.8 billion years), the fact that the Solar System has only existed for the past 4.5 billion years, and the fact that the ingredients for life are everywhere in abundance, why haven’t we found evidence of extraterrestrial intelligence by now? This came to be the basis of Fermi’s Paradox, which remains unresolved to this day.

Interest in Fermi’s question has been piqued in recent years thanks to the sheer number of “potentially habitable” exoplanets discovered in distant star systems. Despite that, all attempts to find signs of technological activity (“technosignatures”) have come up empty. In a recent study, a team of astrobiologists considered the possible resolutions and concluded that only two possibilities exist. Either extraterrestrial civilizations (ETCs) are incredibly rare (or non-existent), or they are deliberately avoiding contact with us (aka. the “Zoo Hypothesis“).

December 15, 2023December 15, 2023 by Scott Alan Johnston

Weather in the Solar System Can Teach Us About Weather on Exoplanets

The way astronomers study planets in our own solar system is surprisingly similar to the way they study exoplanets, despite the latter being orders of magnitude more distant. The key is spectroscopy – examining the wavelengths of light that reach a telescope from a planet’s atmosphere. Different molecules allow different wavelengths to pass through, creating unique patterns in the spectrum and giving scientists clues about the composition of an atmosphere.

Of course, for planets nearby, we can get more details by visiting them – but this is expensive and difficult – we haven’t visited Uranus since Voyager 2 in 1986, for example, so for all intents and purposes, studying Uranus today is done the same way as studying an exoplanet: with a telescope.

A recent review of planetary atmospheres, in our solar system and elsewhere, reveals the incredible complexity and diversity of weather in our solar system, and what we might expect to find around other stars – but also what we don’t yet understand about our near neighbours: there’s plenty of unknowns.

So let’s take a weather-watcher’s tour of the solar system:

December 11, 2023December 11, 2023 by Nancy Atkinson

Amateur Astronomers Found Planets Crashing Into Each Other

Artist impression of two colliding planets.

Astronomy is one of the sciences where amateurs make regular contributions. Over the years, members of the public have made exciting discoveries and meaningful contributions to the scientific process, either through direct observing, citizen science projects, or through combing through open data from the various space missions.

Recently, amateur astronomer Arttu Sainio saw a conversation on X (Twitter) where researchers were discussing the strange behavior of a dimming sun-like star. Intrigued, Arttu decided to look at the data on this star, called Asassn-21qj, on his own. Looking at archival data from NASA’s NEOWISE mission, Sainio was surprised to find that the star had dimmed before, with an unexpected brightening in infrared light two years before the optical dimming event. So, he joined the discussion on social media and shared his finding – which led to more amateurs joining the research, which lead to an incredible discovery.

December 6, 2023December 6, 2023 by Evan Gough

Astronomers Calculate Which Exoplanets Are Most Likely to Have Water

This illustration shows what the hot rocky exoplanet TRAPPIST-1 b could look like. A new method can help determine what rocky exoplanets might have large reservoirs of subsurface water. Credits: NASA, ESA, CSA, J. Olmsted (STScI)

Astronomers know of about 60 rocky exoplanets orbiting in the habitable zones of their stars. When they try to determine how habitable these planets might be, detecting water in their atmospheres plays a huge role. But what if there was another way of measuring the water content in these worlds?

Researchers are developing a way of modelling these worlds to determine how much water they have.

December 1, 2023December 1, 2023 by Beth Johnson

A Planetary System With Six Sub-Neptunes Locked in Perfect Resonance

SCIENCE & EXPLORATION Orbital geometry of HD110067 29/11/2023 457 VIEWS 19 LIKES 492309 ID LIKE DOWNLOAD XFacebookCopy LinkShare DETAILS RELATED Tracing a link between two neighbour planets at regular time intervals along their orbits, creates a pattern unique to each couple. The six planets of the HD110067 system together create a mesmerising geometric pattern due to their resonance-chain. — Credit: Thibaut Roger/NCCR PlanetS

A team of researchers led by University of Chicago astronomer Rafael Luque analyzed data acquired by both NASA’s Transiting Exoplanet Survey Satellite (TESS) and ESA’s CHaracterising ExOPlanet Satellite (Cheops) and found a unique planetary system. Orbiting a star cataloged as HD110067, this system contains six sub-Neptune planets. Incredibly, all six planets are orbiting in direct resonance with each other. The results of the work were published on November 29 in Nature.

November 29, 2023November 29, 2023 by Evan Gough

It Doesn’t Take Much to Get Tilted Planets

Earth's axial tilt (or obliquity) and its relation to the rotation axis and plane of orbit. Credit: Wikipedia Commons

Chinese and Indian astronomers were the first to measure Earth’s axial tilt accurately, and they did it about 3,000 years ago. Their measurements were remarkably accurate: in 1120 BC, Chinese astronomers pegged the Earth’s axial tilt at 24 degrees. Now we know that all of the planets in the Solar System, with the exception of Mercury, have some tilt.

While astronomers have puzzled over why our Solar System’s planets are tilted, it turns out it’s rather normal.

November 26, 2023November 26, 2023 by Matt Williams

Next Generation Space Telescopes Could Use Deformable Mirrors to Image Earth-Sized Worlds

The Roman Space Telescope Coronagraph during assembly of the static optics at NASA’s Jet Propulsion Laboratory Credits: Dr. Eduardo Bendek

Observing distant objects is no easy task, thanks to our planet’s thick and fluffy atmosphere. As light passes through the upper reaches of our atmosphere, it is refracted and distorted, making it much harder to discern objects at cosmological distances (billions of light years away) and small objects in adjacent star systems like exoplanets. For astronomers, there are only two ways to overcome this problem: send telescopes to space or equip telescopes with mirrors that can adjust to compensate for atmospheric distortion.

Since 1970, NASA and the ESA have launched more than 90 space telescopes into orbit, and 29 of these are still active, so it’s safe to say we’ve got that covered! But in the coming years, a growing number of ground-based telescopes will incorporate adaptive optics (AOs) that will allow them to perform cutting-edge astronomy. This includes the study of exoplanets, which next-generation telescopes will be able to observe directly using coronographs and self-adjusting mirrors. This will allow astronomers to obtain spectra directly from their atmospheres and characterize them to see if they are habitable.

November 22, 2023November 22, 2023 by Evan Gough

Wow. JWST Just Found Methane in an Exoplanet Atmosphere

This artist’s rendering shows the warm exoplanet WASP-80 b. When viewed with human eyes, the colour may appear bluish due to the lack of high-altitude clouds and the presence of atmospheric methane identified by NASA’s James Webb Space Telescope. That makes it similar to the planets Uranus and Neptune in our own solar system. Image credit: NASA.

If there’s one chemical that causes excitement in the search for biosignatures on other worlds, it’s methane. It’s not a slam dunk because it has both biotic and abiotic sources. But finding it in an exoplanet’s atmosphere means that planet deserves a closer look.