Gaia is Now Finding Planets. Could it Find Another Earth?

Artist's impression of the ESA's Gaia Observatory. Credit: ESA

The ESA launched Gaia in 2013 with one overarching goal: to map more than one billion stars in the Milky Way. Its vast collection of data is frequently used in published research. Gaia is an ambitious mission, though it seldom makes headlines on its own.

But that could change.

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Why Build Megastructures? Just Move Planets Around to Make Habitable Worlds

An artist view of countless exoplanets. Credit: NASA/JPL-Caltech

In 1960, Freeman Dyson proposed how advanced civilizations could create megastructures that enclosed their system, allowing them to harness all of their star’s energy and multiplying the habitable space they could occupy. In 2015, the astronomical community was intrigued when the star KIC 8462852 (aka. Tabby’s Star) began to dim inexplicably. While an analysis of the star’s light curve in 2018 revealed that the dimming pattern was more characteristic of dust than a solid structure, Tabby’s Star focused attention on the concept of megastructures and their associated technosignatures.

Dyson’s ideas were proposed at a time when astronomers were unaware of the abundance of exoplanets in our galaxy. The first confirmed exoplanet was not discovered until 1992, and that number has now reached 5,514! With this in mind, a team of researchers from Bangalore, India, recently released a paper that presents an alternative to the whole megastructure concept. For advanced civilizations looking for more room to expand, taking planets within their system – or capturing free-floating planets (FFP) beyond – and transferring them into the star’s circumsolar habitable zone (HZ) is a much simpler and less destructive solution.

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Tiny Swarming Spacecraft Could Establish Communications with Proxima Centauri

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

Achieving interstellar travel has been the dream of countless generations, but the challenges remain monumental. Aside from the vast distances involved, there are also the prohibitive energy requirements and the sheer cost of assembling spacecraft that could survive the trip. Right now, the best bet for achieving an interstellar mission within a reasonable timeframe (i.e., a single person’s lifetime) is to build gram-scale spacecraft paired with lightsails. Using high-power laser arrays, these spacecraft could be accelerated to a fraction of the speed of light (relativistic speeds) and reach nearby stars in a few decades.

There are a handful of major projects, like Breakthrough Starshot, that hope to leverage this technology to create spacecraft that could reach Alpha Centauri in a few decades (instead of centuries). This technology also presents other opportunities, like facilitating communications across interstellar distances. This is the idea recently by a team of researchers led by the Initiative for Interstellar Studies (i4is). In a recent paper, they recommended that a swarm of gram-scale spacecraft could rely on their launch laser to maintain optical communications with Earth.

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TESS Finds a Planet That Takes 482 Days to Orbit, the Widest it’s Seen so Far

An artist's rendition of the two planets and star in the TOI-4600 system. One of them has the longest orbit of any planet yet found by TESS. Image Credit: Tedi Vick

We’re rapidly learning that our Solar System, so familiar to us all, does not represent normal.

A couple of decades ago, we knew very little about other solar systems. Astronomers had discovered only a handful of exoplanets, especially around pulsars. But that all changed in the last few years.

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Is Humanity Ready to Realize the Dream of Interstellar Travel?

The 8th Interstellar Symposium was held from July 10th to 13th at McGill University. Credit: Interstellar Research Group (IRG)

For generations, humans have dreamed, speculated, and theorized about the possibility of journeying to distant stars, finding habitable planets around them, and settling down. In time, the children of these bold adventurers would create a new civilization and perhaps even meet the children of Earth. People could eventually journey from one world to another, cultures would mix, and trade and exchanges would become a regular feature. The potential for growth that would come from these exchanges – intellectually, socially, politically, technologically, and economically – would be immeasurable.

Expanding humanity’s reach beyond the Solar System is not just the fevered dream of science fiction writers and futurists. It has also been the subject of very serious scientific research, and interest in the subject is again on the rise. Much like sending crewed missions to Mars, establishing permanent outposts on the Moon, and exploring beyond cislunar space with human astronauts instead of robots – there is a growing sense that interstellar travel could be within reach. But just how ready are we for this bold and adventurous prospect? Whether we are talking about probes vs. crews or technological vs. psychological readiness, is interstellar travel something we are ready to take on?

This was a central question raised at a public outreach event aptly named “Interstellar Travel: Are We Ready?” that took place at the 8th Interstellar Symposium: In Light of Other Suns, held from July 10th to 13th at the University of McGill in Montreal, Quebec. The symposium was hosted by the Interstellar Research Group (IRG), the International Academy of Astronautics (IAA), and Breakthrough Initiatives – in coordination with the University of McGill – and featured guest speakers and luminaries from multiple disciplines – ranging from astronomy and astrophysics to astrobiology, geology, and cosmology.

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Astronomers Confirm First Exoplanet “Thermometer Molecule” that is Typically Used to Study Brown Dwarfs

Artist impression of "hot Jupiter" exoplanet, WASP-31 b. (Credit: ESA/Hubble & NASA)

A recent study published in The Astrophysical Journal Letters examines a rare alloy molecule known as chromium hydride (CrH) and its first-time confirmation on an exoplanet, in this case, WASP-31 b. Traditionally, CrH is only found in large quantities between 1,200 to 2,000 degrees Kelvin (926.85 to 1,726.85 degrees Celsius/1700 to 3,140 degrees Fahrenheit) and used to ascertain the temperature of cool stars and brown dwarfs. Therefore, astronomers like Dr. Laura Flagg in the Department of Astronomy and Carl Sagan Institute at Cornell University refer to CrH as a “thermometer for stars”.

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Watch an Actual Exoplanet Orbit its Star for 17 Years

Artist rendition of exoplanet, Beta Pictoris b, whose partial orbit was recently featured in a time-lapsed video. (Credit: ESO L. Calçada/N. Risinger)

Searching for exoplanets is incredibly difficult given their literal astronomical distances from Earth, which is why a myriad of methods have been created to find them. These include transit, redial velocity, astrometry, gravitational microlensing, and direct imaging. It is this last method that was used to recently create a time-lapse video that compresses a mind-blowing 17 years of the partial orbit of exoplanet, Beta Pictoris b, into 10 seconds. The data to create the video was collected between 2003 and 2020, it encompasses approximately 75 percent of the total orbit, and marks the longest time-lapse video of an exoplanet ever produced.

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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.

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This Jupiter-Sized Exoplanet is Unusual for Several Reasons

Artist illustration of a warm Jupiter gas-giant exoplanet (right) orbiting its parent star, along with several smaller exoplanets. (Credit: Detlev Van Ravenswaay/Science Photo Library)

In a recent study published in the Monthly Notices of the Royal Astronomical Society, a team of international researchers examined exoplanet TOI-4860 b, which is located approximately 80 parsecs (261 light-years) from Earth and has an orbital period of approximately 1.52 days around a low-mass star, or a star smaller than our Sun. Exoplanets orbiting so close to their parent stars aren’t uncommon and commonly known as “hot Jupiters”.

However, TOI-4860 b is unique due its relative size compared to its parent star, along with its lower surface temperatures compared to “hot Jupiters” and possessing large amounts of heavy elements. These attributes are why researchers are classifying TOI-4680 b as a “warm Jupiter”, and could challenge traditional planetary systems formation models while offering new insights into such processes, as well.

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The PLATO Mission Could be the Most Successful Planet Hunter Ever

Artist's impression of the ESA's PLATO mission. Credit: ESA/ATG medialab

In 2026, the European Space Agency (ESA) will launch its next-generation exoplanet-hunting mission, the PLAnetary Transits and Oscillations of stars (PLATO). This mission will scan over 245,000 main-sequence F, G, and K-type (yellow-white, yellow, and orange) stars using the Transit Method to look for possible Earth-like planets orbiting Solar analogs. In keeping with the “low-hanging fruit” approach (aka. follow the water), these planets are considered strong candidates for habitability since they are most likely to have all the conditions that gave rise to life here on Earth.

Knowing how many planets PLATO will likely detect and how many will conform to Earth-like characteristics is essential to determining how and where it should dedicate its observation time. According to a new study that will be published shortly in the journal Astronomy & Astrophysics, the PLATO mission is likely to find tens of thousands of planets. Depending on several parameters, they further indicate that it could detect a minimum of 500 Earth-sized planets, about a dozen of which will have favorable orbits around G-type (Sun-like) stars.

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