CLOSE
M. Weiss/CfA
M. Weiss/CfA

New "Super-Earth" Exoplanet May Have Water—and Life

M. Weiss/CfA
M. Weiss/CfA

A possible new Earth-like world has been found, and it’s giant, according to a study [PDF] published today in Nature. LHS 1140b, an exoplanet a mere 40 light-years away, is 40 percent larger than Earth while orbiting a tiny red dwarf star one-fifth the size of our own. That might not seem like the recipe for “Earth” or “life,” but the planet resides in its star's habitable zone, the slim "Goldilocks" orbit at which water can exist as a stable liquid. It also exhibits characteristics of a rocky world, which is significant: where there’s water and rock, there’s a possibility for life.

The world was discovered using the transit photometry method of exoplanet detection. As a planet crosses in front of a star, the star dims slightly. Think of an annular solar eclipse: When the Moon crosses in front of the Sun but is too far from the Earth to blot out the Sun entirely, the day is dimmed but isn’t plunged into darkness. The same principle applies here, though on a much finer scale. The amount the star dims also reveals its size.

So what makes this exoplanet so special? What about the TRAPPIST-1 worlds we were celebrating last month? That party might have been a bit premature. Scientists have only measured the density of one of those worlds, and turns out: It isn’t rocky. So … maybe none of the others are, either. While they’re certainly Earth-sized and in their star's habitable zone, imagining Earth without rocks is something of a challenge. LHS1140b, though, is rocks for days, and now that scientists know it's there, the plan is to study the hell out of it.

Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics and lead author of the study tells mental_floss that the team studying LHS 1140b has been allocated Hubble Space Telescope time to do another transit observation. They’ve also applied for further Hubble time and x-ray telescope time in order to assess the high-energy environment the planet may be experiencing. Here on Earth, they hope also to use both Magellan telescopes at Las Campanas Observatory in Chile, and their Chilean collaborators have applied to use three of that country’s Very Large Telescopes. "So, basically, we're hoping to throw everything we have at this planet!" he says.

The James Webb Space Telescope, set to launch next year, will really unlock the mysteries of LHS 1140b. "We hope to be able to detect not just that this planet has an atmosphere but also what it's made of. In particular, [James Webb Space Telescope] may be sensitive to carbon dioxide, water, methane, and ozone," he says. The Giant Magellan Telescope and European Extremely Large Telescope, both under construction, might be able to detect molecular oxygen as well, as the strongest features of that molecule exist at more optical wavelengths. "If we can do all of these things, we might have a pretty clear picture about the atmosphere, and what's in it, and hopefully we can even say that's very similar to the Earth's."

Dittmann's Harvard colleague David Charbonneau, a co-author of the study, tells mental_floss that until James Webb launches, there’s much work to do. "First, we need to figure out the ultraviolet emission from the star," he says. "Some red dwarfs have huge amounts of UV light, which can be devastating to the atmosphere, and life! So, we are planning to use the Hubble Space Telescope to learn that. Also, there is one (and only one) good ground-based opportunity to study the planet from Chile this fall, so we are trying to have every large telescope in Chile point at the system on that night. We are calling it Transit Night." That will take place on October 26, 2017.

While ground-based observations won't be as penetrating as what the James Webb Space Telescope will be able to do, they will tell scientists if the atmosphere has, for example, lots of hydrogen and helium ("which would make the atmosphere fluffy and easy to detect," he says) and thus not Earth-like. Once the telescopes in development go online, however, there is even a chance that they can find signs of life. "[The Giant Magellan Telescope] can detect oxygen, which is an atmospheric biosignature gas," he says, though oxygen alone isn't enough. "Maybe, unlike Earth, the oxygen is made by a different process, such as UV light breaking apart water in the atmosphere. The [James Webb Space Telescope] observations will be sensitive to the other molecules—methane, water, carbon dioxide—that would allow us to know whether the oxygen really is produced by life."

LHS 1140b was first detected by Harvard’s MEarth (pronounced "mirth") project, and confirmed by the European Southern Observatory’s High Accuracy Radial velocity Planet Searcher. The planet is thought to be at least five billion years old, and its size and density suggest a dense iron core beneath its rocky surface.

nextArticle.image_alt|e
Scott Butner, Flickr // CC BY-NC-ND 2.0
arrow
Space
Look Up! The Lyrid Meteor Shower Arrives Saturday Night
Scott Butner, Flickr // CC BY-NC-ND 2.0
Scott Butner, Flickr // CC BY-NC-ND 2.0

There is a thin line between Saturday night and Sunday morning, but this weekend, look up and you might see several of them. Between 11:59 p.m. on April 21 and dawn on Sunday, April 22, the Lyrid meteor shower will peak over the Northern Hemisphere. Make some time for the celestial show and you'll see a shooting star streaking across the night sky every few minutes. Here is everything you need to know.

WHAT IS THE LYRID METEOR SHOWER?

Every 415.5 years, the comet Thatcher circles the Sun in a highly eccentric orbit shaped almost like a cat's eye. At its farthest from the Sun, it's billions of miles from Pluto; at its nearest, it swings between the Earth and Mars. (The last time it was near the Earth was in 1861, and it won't be that close again until 2280.) That's quite a journey, and more pressingly, quite a variation in temperature. The closer it gets to the Sun, the more debris it sheds. That debris is what you're seeing when you see a meteor shower: dust-sized particles slamming into the Earth's atmosphere at tens of thousands of miles per hour. In a competition between the two, the Earth is going to win, and "shooting stars" are the result of energy released as the particles are vaporized.

The comet was spotted on April 4, 1861 by A.E. Thatcher, an amateur skywatcher in New York City, earning him kudos from the noted astronomer Sir John Herschel. Clues to the comet's discovery are in its astronomical designation, C/1861 G1. The "C" means it's a long-period comet with an orbit of more than 200 years; "G" stands for the first half of April, and the "1" indicates it was the first comet discovered in that timeframe.

Sightings of the Lyrid meteor shower—named after Lyra, the constellation it appears to originate from—are much older; the first record dates to 7th-century BCE China.

HOW CAN I SEE IT?

Saturday night marks a first quarter Moon (visually half the Moon), which by midnight will have set below the horizon, so it won't wash out the night sky. That's great news—you can expect to see 20 meteors per hour. You're going to need to get away from local light pollution and find truly dark skies, and to completely avoid smartphones, flashlights, car headlights, or dome lights. The goal is to let your eyes adjust totally to the darkness: Find your viewing area, lay out your blanket, lay down, look up, and wait. In an hour, you'll be able to see the night sky with great—and if you've never done this before, surprising—clarity. Don't touch the smartphone or you'll undo all your hard ocular work.

Where is the nearest dark sky to where you live? You can find out on the Dark Site Finder map. And because the shower peaks on a Saturday night, your local astronomy club is very likely going to have an event to celebrate the Lyrids. Looking for a local club? Sky & Telescope has you covered.

WHAT ELSE IS GOING ON UP THERE?

You don't need a telescope to see a meteor shower, but if you bring one, aim it south to find Jupiter. It's the bright, unblinking spot in the sky. With a telescope, you should be able to make out its stripes. Those five stars surrounding it are the constellation Libra. You'll notice also four tiny points of light nearby. Those are the Galilean moons: Io, Europa, Ganymede, and Callisto. When Galileo discovered those moons in 1610, he was able to prove the Copernican model of heliocentricity: that the Earth goes around the Sun.

THERE'S BAD WEATHER HERE! WHAT DO I DO?

First: Don't panic. The shower peaks on the early morning of the 22nd. But it doesn't end that day. You can try again on the 23rd and 24th, though the numbers of meteors will likely diminish. The Lyrids will be back next year, and the year after, and so on. But if you are eager for another show, on May 6, the Eta Aquariids will be at their strongest. The night sky always delivers.

arrow
Space
New NASA Satellite Called TESS Could Discover Thousands of New Planets

Since NASA’s Kepler spacecraft launched in 2009, the space agency has found and confirmed a whopping 2343 new planets. Of those, 30 are considered to be situated in a “habitable zone,” an area in which a planet’s surface could theoretically contain water.

A new satellite, set to launch today, is expected to find thousands more planets outside of our solar system, known as exoplanets. TESS, short for the Transiting Exoplanet Survey Satellite, is NASA’s latest effort to plumb the depths and darkness of outer space in search of other Earth-like planets—including those that could potentially support life.

TESS is slated to complete a two-year survey of the “solar neighborhood,” a general region which comprises more than 200,000 of the brightest nearby stars. To find these outlier planets, NASA scientists will be keeping an eye out for temporary changes in brightness, which indicate that a planet is blocking its host star.

According to Martin Still, the program scientist working on the TESS mission, the launch comes “with certainty” that TESS will find many nearby exoplanets. "We expect to find a whole range of planet sizes, between planets the size of Mercury or even the Moon—our Moon—to planets the same size as Jupiter and everything in between,” Still said in a NASA interview.

While the Kepler mission was considered a major success, NASA noted that most of the planets it recorded are those that orbit faint, faraway stars, making it difficult to conduct follow-up observations. The stars that TESS plans to survey will be 30 to 100 times brighter than those observed by its predecessor. This allows for newly detected planets and their atmospheres to be characterized more easily.

“Before Kepler launched, we didn't know for sure if Earth-sized planets existed,” Elisa V. Quintana, a NASA astrophysicist, told Reddit. “Kepler was a statistical survey that looked at a small patch of sky for four years and taught us that Earths are everywhere. TESS is building on Kepler in the sense that TESS wants to find more small planets but ones that orbit nearby, bright stars. These types of planets that are close to us are much more easy to study, and we can measure their masses from telescopes here on Earth.”

The most common categories of exoplanets are Earth- and Super Earth–sized masses—the latter of which are larger than Earth but smaller than Uranus and Neptune.

TESS is scheduled to launch from the Cape Canaveral Air Force Station in Florida on a SpaceX Falcon 9 rocket at 6:32pm EDT today.

For more information about TESS, check out this video from NASA.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios