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.
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.
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.
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?
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”.
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.
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.
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.
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 journalAstronomy & 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.