Astronomers are Starting to Find Planets in Much Longer Orbits. Cooler, More Habitable Planets

This artist’s view shows the planet orbiting the young star Beta Pictoris. This exoplanet is the first to have its rotation rate measured. Its eight-hour day corresponds to an equatorial rotation speed of 100 000 kilometres/hour — much faster than any planet in the Solar System.

We’re getting better and better at detecting exoplanets. Using the transit method of detection, the Kepler Space Telescope examined over 530,000 stars and discovered over 2,600 explanets in nine years. TESS, the successor to Kepler, is still active, and has so far identified over 1800 candidate exoplanets, with 46 confirmed.

But what if, hidden in all that data, there were even more planets? Astronomers at Warwick University said they’ve found one of these “lost” planets, and that they think they’ll find even more.

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1 in 10 Red Giants are Covered in Spots, and They Rotate Surprisingly Quickly

Artist's impression of a red giant star. If the star is in a binary pair, what happens to its sibling? Credit:NASA/ Walt Feimer

Sunspots are common on our Sun. These darker patches are cooler than their surroundings, and they’re caused by spikes in magnetic flux that inhibit convection. Without convection, those areas cool and darken.

Lots of other stars have sunspots, too. But Red Giants (RGs) don’t. Or so astronomers thought.

A new study shows that some RGs do have spots, and that they rotate faster than thought.

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Deep Down in Ocean Worlds, it’s Difficult to Tell Where the Oceans End and the Rock Begins

This artist’s concept shows a hypothetical planet covered in water around the binary star system of Kepler-35A and B. The composition of such water worlds has fascinated astronomers and astrophysicists for years. (Image by NASA/JPL-Caltech.)

We all know what water is. And what rock is. The difference is crystal clear. Well, here on Earth it is.

But on other worlds? The difference might not be so clear.

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More Evidence that Europa’s Oceans Could be Habitable

A "true color" image of the surface of Jupiter's moon Europa as seen by the Galileo spacecraft. In 2030, the Europa Clipper mission will start its close flybys of this ocean world. Image credit: NASA/JPL-Caltech/SETI Institute
A "true color" image of the surface of Jupiter's moon Europa as seen by the Galileo spacecraft. In 2030, the Europa Clipper mission will start its close flybys of this ocean world. Image credit: NASA/JPL-Caltech/SETI Institute

At first glance, Jupiter’s moon Europa doesn’t seem much like Earth. It’s a moon, not a planet, and it’s covered in ice. But it does have one important thing in common with Earth: a warm, salty ocean.

Now there’s even more evidence that Europa’s sub-surface ocean is habitable.

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A 2nd Planet has been Confirmed for Proxima Centauri

An artist's illustration of the Proxima Centauri system. Proxima b is on the left, while Proxima C is on the right. Image Credit: Lorenzo Santinelli

Our closest stellar neighbour is Proxima Centauri, a small red dwarf star about 4.2 light years away from us. It’s the third member of the Alpha Centauri group, and even though it’s so close, it can’t be seen with the naked eye. In 2016 astronomers discovered a planet orbiting Proxima Centuari, named Proxima Centauri b. That planet was confirmed only a few days ago.

Now, astronomers have confirmed the existence of a second planet, Proxima Centauri c.

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Astronomers Have Found the Star/Exoplanet Combo That’s the Best Twin to the Sun/Earth

An artist's illustration of TOI 700d, an Earth-size exoplanet that TESS found in its star's habitable zone. Image Credit: NASA

At times, it seems like there’s an indundation of announcements featuring discoveries of “Earth-like” planets. And while those announcements are exciting, and scientifically noteworthy, there’s always a little question picking away at them: exactly how Earth-like are they, really?

After all, Earth is defined by its relationship with the Sun.

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Ocean Circulation Might Be the Key to Finding Habitable Exoplanets

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)
Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

We’ve found thousands and thousands of exoplanets now. And spacecraft like TESS will likely find thousands and thousands more of them. But most exoplanets are gassy giants, molten hell-holes, or frozen wastes. How can we find those needles-in-the-haystack habitable worlds that may be out there? How can we narrow our search?

Well, first of all, we need to find water. Oceans, preferably, since that’s where life began on Earth. And according to a new study, those oceans need to circulate in particular ways to support life.

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NASA’s Perseverance Rover is Going to Jezero Crater, Which is Looking Better and Better as a Place to Search for Evidence of Past Life on Mars

Jezero Crater on Mars is the landing site for NASA's Mars 2020 rover. Image Credit: NASA/JPL-Caltech/ASU

In 2018, NASA decided that the landing site for its Mars 2020 Perseverance rover would be the Jezero Crater. At the time, NASA said the Jezero Crater was one of the “oldest and most scientifically interesting landscapes Mars has to offer.” That assessment hasn’t changed; in fact it’s gotten stronger.

A new research paper says that the Jezero Crater was formed over time periods long enough to promote both habitability, and the preservation of evidence.

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The Perfect Stars to Search for Life On Their Planets

This infographic compares the characteristics of three classes of stars in our galaxy: Sunlike stars are classified as G stars; stars less massive and cooler than our Sun are K dwarfs; and even fainter and cooler stars are the reddish M dwarfs. The graphic compares the stars in terms of several important variables. The habitable zones, potentially capable of hosting life-bearing planets, are wider for hotter stars. The longevity for red dwarf M stars can exceed 100 billion years. K dwarf ages can range from 15 to 45 billion years. And, our Sun only lasts for 10 billion years. The relative amount of harmful radiation (to life as we know it) that stars emit can be 80 to 500 times more intense for M dwarfs relative to our Sun, but only 5 to 25 times more intense for the orange K dwarfs. Red dwarfs make up the bulk of the Milky Way's population, about 73%. Sunlike stars are merely 6% of the population, and K dwarfs are at 13%. When these four variables are balanced, the most suitable stars for potentially hosting advanced life forms are K dwarfs. Credits: NASA, ESA and Z. Levy (STScI)

We tend to think of our Earthly circumstances as normal. A watery, temperate world orbiting a stable yellow star. A place where life has persisted for nearly 4 billion years. It’s almost inevitable that when we think of other places where life could thrive, we use our own experience as a benchmark.

But should we?

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TESS Finds its First Earth-Sized World in the Habitable Zone of a Star

An artist's illustration of TOI 700d, an Earth-size exoplanet that TESS found in its star's habitable zone. Image Credit: NASA

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.

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