Heat from radioactivity, not starlight, could warm planets enough to allow liquid water to exist on their surfaces.
Radioactive isotopes such as uranium-238, thorium-232, and potassium-40 pepper Earth's crust and mantle. As these unstable radionuclides decay, they generate a small amount of power—roughly one-thirty-thousandth that received from the Sun. But researchers have now proposed that some planets, particularly ones that form near the center of our Milky Way Galaxy, might possess enough of these radioactive isotopes to generate sufficient heat to keep their surfaces from freezing entirely solid.
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Star Blasts Own Planets Into Shattered Corpses, Devours Remains
In 2015, a international team of astronomers watched a white dwarf star gobbling up the planets in its very own system like a mother devouring its young.
Their study , now accepted to the Astrophysical Journal for review, kicks off an entirely new field of study, as Popular Mechanics reports : "necroplanetology."
White dwarfs are the remains of a stellar core that burned up all the hydrogen it previously used to fuel its fusion reactions. They are also extremely dense, in some instances compacting the mass of the Sun into the volume of Earth.
Discovery Alert: New Planet — a Heavyweight, but Habitable?
Artist's rendering of a "super Earth," a planet larger than Earth but smaller than Neptune. A newly discovered star system includes three worlds in this size-range — one of them in the star's "habitable zone." Image credit: ESO/M. Kornmesser
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The discovery: This planet joins a mysterious group — possibly habitable worlds in tight orbits around small, red-dwarf stars in our galaxy. GJ 1061d is part of a system of at least three planets a mere 12 light-years from Earth. Its surface temperature might be just right for liquid water.
How To See The Planets At Their Closest For 20 Years: What You Can See In The Night Sky This Week
Each Monday I pick out the northern hemisphere's celestial highlights for the week ahead, but be sure to check my main feed for more in-depth articles on stargazing, eclipses and astronomy.
This week it's all about the planets. First—before sunrise—the "ringed planet" Saturn, "red planet" Mars and "giant planet" Jupiter appear as close together as they have for 20 years. Then comes a rare post-sunset trip for bright Venus into the "Seven Sisters" stars of the Pleaides star cluster. That's going to be a beautiful and and much-photographed sight.
This may worth something:
News | WFIRST Will Use Warped Space-time to Help Find Exoplanets
NASA's Wide Field Infrared Survey Telescope (WFIRST) will search for planets outside our solar system toward the center of our Milky Way galaxy, where most stars are. Studying the properties of exoplanet worlds will help us understand what planetary systems throughout the galaxy are like and how planets form and evolve.
Combining WFIRST's findings with results from NASA's Kepler and Transiting Exoplanet Survey Satellite (TESS) missions will complete the first planet census that is sensitive to a wide range of planet masses and orbits, bringing us a step closer to discovering habitable Earth-like worlds beyond our own.
NASA Selects Six Early Career Planetary Scientists | NASA
Astronomers Define the "Really Habitable Zone".
Exoplanets are a hot topic in space science right now. We know of about 4,000 confirmed exoplanets, with many more on the way. We've come a long way from a few decades ago, when as far as we knew, our Solar System was the only one with a habitable world. What else were we supposed to think?
The Kepler mission changed all that. Our knowledge of exoplanets grew in leaps and bounds, and along with the discovery of all those distant planets, we began to refine our criteria for what a habitable world might look like.
April 2020 guide to the bright planets; enjoy Venus | Bonners Ferry, Idaho |
Venus will reach its greatest illuminated extent on April 28, at 1 a.m. UTC. That's 7 p.m. MDT and 6 p.m. PDT.
The view of the moon and morning planets from the Southern Hemisphere (Cape Town, South Africa) before sunrise April 16. Around mid-month at the equator, Mercury rises about one hour before the sun, and at 35 degrees south latitude, Mercury rises about 1 1/2 hours before sunrise.
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Venus – the brightest planet – blazes mightily in the western sky after sunset, starting out the month in close conjunction with the Pleiades star cluster. It's the only bright planet to light up these April evenings all month long.
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