To date, astronomers have confirmed the existence of 4,422 extrasolar planets in 3,280 star systems, with an additional 7,445 candidates awaiting confirmation. Of these, only a small fraction (165) have been terrestrial (aka. rocky) in nature and comparable in size to Earth – i.e., not “Super-Earths.” And even less have been found that are orbiting within their parent star’s circumsolar habitable zone (HZ).
In the coming years, this is likely to change when next-generation instruments (like James Webb) are able to observe smaller planets that orbit closer to their stars (which is where Earth-like planets are more likely to reside). However, according to a new study by researchers from the University of Napoli and the Italian National Institute of Astrophysics (INAF), Earth-like biospheres may be very rare for exoplanets.
Continue reading “Most Exoplanets won’t Receive Enough Radiation to Support an Earth-Like Biosphere”
In the past few decades, the study of exoplanets has grown by leaps and bounds, with 4296 confirmed discoveries in 3,188 systems and an additional 5,634 candidates awaiting confirmation. Because of this, scientists have been able to get a better idea about the number of potentially-habitable planets that could be out there. A popular target is stars like our own, which are known as G-type yellow dwarfs.
Recently, an international team of scientists (led by researchers from the NASA Ames Research Center) combined data from by the now-defunct Kepler Space Telescope and the European Space Agency’s (ESA) Gaia Observatory. What this revealed is that half of the Sun-like stars in our Universe could have rocky, potentially-habitable planets, the closest of which could be in our cosmic backyard!
Continue reading “Based on Kepler Data, There’s a 95% Chance of an Earth-Like Planet Within 20 Light-Years”
NASA’s TESS planet-finding spacecraft completed its primary mission about 3 months ago. TESS’s (Transiting Exoplanet Survey Satellite) job was to search the brightest stars nearest to Earth for transiting exoplanets. It found 74 confirmed exoplanets, with another ~1200 candidates awaiting confirmation.
It surveyed 75% of the sky during its two-year primary mission, and now NASA has released a composite image of the northern sky, made up of more than 200 individual images.
Continue reading “Time Flies. NASA Releases a Mosaic of TESS’ View of the Northern Sky After Two Years of Operation”
Exoplanets have been a particularly hot topic of late. More than 4000 of them have been discovered since the first in 1995. Now one more can potentially be added to the list. This one is orbiting Gliese 3470, a red dwarf star located in the constellation Cancer. What makes this discovery particularly interesting is that this planet wasn’t discovered by any professional astronomers using high tech equipment like the Kepler Space Telescope. It was found entirely by amateurs.
Continue reading “Saturn-sized Planet Found in the Habitable Zone of Another Star. The First Planet Completely Discovered by Amateur Astronomers”
In the past few decades, astronomers have confirmed the existence of thousands of planets beyond our Solar System. Over time, the process has shifted from discovery to characterization in the hopes of finding which of these planets are capable of supporting life. For the time being, these methods are indirect in nature, which means that astronomers can only infer if a planet is inhabitable based on how closely it resembles Earth.
To aid in the hunt for “potentially habitable” exoplanets, a team of Cornell researchers recently created five models that represent key points in Earth’s evolution. These “snapshots” of what Earth looked like during various geological epochs could greatly enhance the search for extra-terrestrial life by providing a more complete picture of what a life-bearing planet could look like.
Continue reading “Five Snapshots of how the Earth Looked at Key Points in its History Could Help us Find Habitable Exoplanets”
NASA’s TESS (Transiting Exoplanet Survey Satellite) has found its first Earth-sized planet located in the habitable zone of its host star. The find was confirmed with the Spitzer Space Telescope. This planet is one of only a few Earth-sized worlds ever found in a habitable zone.
Continue reading “TESS Finds its First Earth-Sized World in the Habitable Zone of a Star”
Earthlings are fortunate. Our planet has a robust magnetic shield. Without out magnetosphere, the Sun’s radiation would’ve probably ended life on Earth before it even got going. And our Sun is rather tame, in stellar terms.
What’s it like for exoplanets orbiting more active stars?
Continue reading “Without a Magnetosphere, Planets Orbiting Flare Stars Don’t Stand a Chance”
Plate tectonics have played a vital role in the geological evolution of our planet. In addition, many scientists believe that Earth’s geologically activity may have played an important role in the evolution of life – and could even be essential for a planet’s habitability. For this reason, scientists have long sought to determine how and when Earth’s surface changed from molten, viscous rock to a solid crust that is constantly resurfacing.
In the past, the number of known exoplanets has exploded, with 4093 confirmed detections so far (and another 4,727 candidates awaiting confirmation). With the discovery of so many planets that are dozens, hundreds, or even thousands of light years away, a great deal of attention has understandably been directed to our nearest stellar neighbors. Could planets be right next door, with the possibility of life being there as well?
While a potentially-habitable planet was recently discovered around Proxima Centauri (Proxima b), Alpha Centauri remains something of a question mark. But thanks to a recent study from the Georgia Institute of Technology (GIT), we might be getting closer to determining if this neighboring system supports life. In a twist, the study revealed that one of the stars in the binary system is more likely to be habitable than the other.
Continue reading “Of the Two Stars in Alpha Centauri, One is Probably More Habitable than the Other”
In order to be considered habitable, a planet needs to have liquid water. Cells, the smallest unit of life, need water to carry out their functions. For liquid water to exist, the temperature of the planet needs to be right. But how about the size of the planet?
Without sufficient mass a planet won’t have enough gravity to hold onto its water. A new study tries to understand how size affects the ability of a planet to hold onto its water, and as a result, its habitability.
Continue reading “Planet Sizes Matter for Habitability Too.”