WEIGHING THIS TINY PLANET COULD HELP THE SEARCH FOR ALIEN LIFE
THIS MARS-SIZED EXOPLANET IS A BIG DEAL
(The Kepler-138 Solar System
Danielle Futselaar, SETI Institute)
Not drawn to scale. The illustration shows the Mars-sized Kepler 138b in the foreground, with blurs symbolizing how 138b’s gravity affects the orbits of its neighbors.
There may be “no place like home” in The Wizard Of Oz, but in the Milky Way, there could be billions of planets that are like Earth. But really big planets are a lot easier to spot than Earth-size planets, so our view of what’s out there is skewed.
“Planets smaller than Earth may well be the most common type of exoplanets, but since they are much harder to detect, there are not many we can study in detail,” Daniel Jontof-Hutter, an astronomer at Pennsylvania State University, told Popular Science.
Now, for the first time, Jontof-Hutter’s team has managed to measure the size and mass of a planet that’s actually 10 times smaller than Earth. Up until now, the smallest planet we’ve weighed was almost twice as massive as our home planet.
Two hundred light-years away, Kepler 138b is a small, baking hot planet. Scientists first spotted it by watching it eclipse its star, and the tiny shadow it created revealed that it was about the size of Mars. Now, thanks to new mass measurements, with which researchers calculates Kepler 138b’s density, we know the planet is not gassy or icy or metallic, but rocky like our own.
The typical way of measuring a planet’s mass is by seeing how much the planet’s gravity makes its star wobble. But since smaller planets have less gravity, the star wobbles they induce are minuscule. So to get the mass of Kepler 138b, Jontof-Hutter’s team instead measured how the planet’s gravity affected the orbits of its neighboring planets.
“Each planet accelerates and slows down ever so slightly because of the gravity of its neighbors,” explains Jontof-Hutter. So the gravity bump from Kepler 138b changed the length of its neighbors’ orbits ever so slightly. The change in time revealed that Kepler 138b weighs in at about 7 percent of Earth’s mass.
This method of measuring mass is not new, but it only works in certain star systems—like Kepler 138, where multiple planets are orbiting close to their sun, and where there’s lots and lots of data to analyze and compare.
The fact that scientists have measured the mass of this extremely distant, tiny planet is amazing. If scientists can study more of these Earth-size or smaller exoplanets, it will tell us how unique (or not) our solar system is. And that has implications for our chances of finding life elsewhere in the galaxy.
LASER-ARMED CRYO ROBOTS COULD EXPLORE EUROPA FOR ALIEN LIFE
THEY’RE STARTING WITH GLACIERS AND WORKING THEIR WAY UP TO SPACE
-A re-mastered photo of Europa’s surface. For more information, read Francie Diep’s Story on the nearly-true colors of Europa
What has lasers, a torpedo-shaped body, and is capable of tunneling where no one has tunneled before? VALKYRIE, one of the ‘cryobots’ that is paving the way towards exploring icy moons like Europa in the future.
Jupiter’s moon Europa is considered a prime candidate for extraterrestrial life with a saltwater ocean buried under a thick crust of ice. Getting to the water from the surface is a difficult task, but some roboticists think they’ve found the answer in robots designed to function well in the cold–cryobots, for short.
(Concept art of VALKYRIE cryobot from Stone Aerospace
As Astrobiology Magazine reports, one group testing cryobots is Stone Aerospace, which developed the VALKYRIE (Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer) a few years ago and has been testing it ever since, hoping that one day it will join a Europa mission. VALKYRIE (not to be confused with another NASA robot named Valkyrie) cuts through the ice with lasers, creating stable tunnels that she can slide through.
This summer, VALKYRIE will be tested again at the Matanuska glacier in Alaska, where it successfully completed tests last summer. This summer it will be testing an instrument that can hunt for microbes beneath the glacier’s surface, a technology that would be vitally important to finding life on Europa.
The first mission to Europa will likely be the Europa Clipper, launching sometime in the 2020s. Instead of landing on the surface, or drilling underneath the ice, it will stay aloft, making excursions into the moon’s atmosphere. There will still be plenty of cool tech onboard to search for signs of life. And who knows, the mission after that might be equipped with a cryobot, which can dig a little deeper into Europa’s surface.
VALKYRIE will have some competition though. Stone Aerospace is also testing ARTEMIS, a robot that will be tested in Antarctica this fall, joining a growing crowd of autonomous vehicles mapping that continent’s sea ice, and other teams are working on lamprey-like soft robots that could explore Europa’s oceans.
AMAZING SUNSET SKY SHOW
If you love stargazing, there’s a date you need to mark on your calendar. It’s June.
That’s right, the whole month!
Throughout the month of June 2015, the two brightest planets in the night sky, Venus and Jupiter, are going to converge for a jaw-dropping close encounter. You don’t want to miss any of the action.
Venus and Jupiter are converging for a must-see close encounter at the end of June. It could be the best backyard sky show of 2015.
When the sun goes down, step outside and look west. You don’t have to wait until the sky fades to black. Venus and Jupiter are so bright, you can see then shining through the twilight. In fact, some people say the planets are especially beautiful when they are surrounded by the cobalt hue of the early evening sky–so don’t wait.
During the first two weeks of June, Venus and Jupiter converge until they are only about 10 degrees apart. For reference, this means they would just fit together inside the bowl of the Big Dipper. You could hide them both, simultaneously, behind the palm of your outstretched hand.
This is pretty close, but by the end of the month this distance will shrink by a factor of 30.
In fact, every night in June, the separation between Venus and Jupiter will visibly shrink.
One good night to check on their progress is June 12th. After dark, scan the sky around Venus with binoculars. You can see the Beehive Star cluster! Venus will be passing right by it.
On June 18th, Venus and Jupiter will be only 6 degrees apart. Now you can hide the two behind just two or three of your fingers with your arm outstretched.
On June 19th, something exciting happens: the crescent Moon joins the show. On that evening, the Moon, Venus and Jupiter will form a bright isosceles triangle in the sunset sky. Isosceles means that two sides of the triangle are the same length. This is how most sky watchers in North America will see it.
One night later, on June 20th, the vertices rearrange themselves, forming yet another isosceles triangle. Never has a geometry lesson been so beautiful.
The nights of June 19th and 20th, by the way, are good nights to look through a telescope. Even a small telescope will show you the fat crescent phase of Venus, the cloudtops and largest moons of Jupiter, and the rugged terrain of Earth’s own Moon. Swing your optics around the triangle for a fast-paced heavenly show.
The main event occurs on June 30th. On that night, Venus and Jupiter will be a jaw-dropping 1/3rd of a degree apart. That’s less than the diameter of a full Moon. You’ll be able to hide the pair not just behind the palm of your outstretched hand, but behind your little pinky finger.
Wow. Here’s hoping you spend a lot of time under the stars and planets in June.
For more news about bright lights in the night sky, stay tuned to Science.nasa.gov
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA
Expedition 43 Crew Returns to Earth Safely
The three-person crew of Expedition 43 has safely touched down in Kazakhstan.
Expedition 43 was helmed by NASA’s Terry Virts, who was joined by Flight Engineers Samantha Cristoforetti (European Space Agency) and Anton Shkaplerov (Roscosmos). Their return marks the end of a 199-day sojourn aboard the International Space Station, during which the crew took part in hundreds of scientific investigations.
One of the most notable investigations was the launch of the One Year Mission, a NASA study that aims to better understand the long-term effects of spaceflight on the human body. The crew also investigated new synthetic muscle technologies, infectious diseases and bone loss.
Upon completion of her mission, Cristoforetti set a new record for single mission duration by a female astronaut, a distinction previously claimed by NASA’s Suni Williams.
Presently, the Expedition 44 crew is in charge of the International Space Station. Russia’s Gennady Padalka is in command, and is joined by NASA’s Scott Kelly and Roscosmos’ Mikhail Kornienko. They will be joined by NASA’s Kjell Lindgren, Roscosmos’ Oleg Kononenko and Japan Aerospace Exploration Agency astronaut Kimiya Yui in late July.
WORK- EXPERIENCE SCHOOL BOY DISCOVERS A NEW PLANET
Artist rendition of WASP-142b (on the left), as seen from a hypothetical moon.
David A. Hardy
The WASP software was impressive, enabling me to search through hundreds of different stars, looking for ones that have a planet. The planet is the same size as Jupiter, but orbits its star in only two days
A 15-yr-old schoolboy has discovered a new planet orbiting a star 1000 light years away in our galaxy. Tom Wagg was doing work-experience at Keele University when he spotted the planet by finding a tiny dip in the light of a star as a planet passed in front of it.
“I’m hugely excited to have a found a new planet, and I’m very impressed that we can find them so far away”, says Tom, now aged 17. It has taken two years of further observations to prove that Tom’s discovery really is a planet.
Tom found the planet by looking at data collected by the WASP (Wide Angle Search for Planets) project, which surveys the night skies monitoring millions of stars to look for the tell-tale tiny dips (transits) caused by planets passing in front of their host star.
Tom’s planet has been given the catalogue number WASP-142b, being the 142nd discovery by the WASP collaboration. It is in the Southern constellation of Hydra. While astronomers worldwide have now found over 1000 extra-solar planets, Tom is possibly the youngest ever to have done so.
“The WASP software was impressive, enabling me to search through hundreds of different stars, looking for ones that have a planet”, says Tom. The planet is the same size as Jupiter, but orbits its star in only two days. With such a short orbital period the transits occur frequently, making such planets much easier to find.
While the planet is much too far away to see directly, an artist’s impression shows how it might look. The hemisphere facing the star is hot, blasted by the irradiation from the star, while the other hemisphere is much cooler.
Tom, a pupil at Newcastle-under-Lyme School who has always been keen on science, asked for the work-experience week after learning that Keele University had a research group studying extra-solar planets.
“Tom is keen to learn about science, so it was easy to train him to look for planets”, says Professor Coel Hellier, who leads the WASP project at Keele. Tom has since achieved 12 GCSEs, all at A*, and wants to study physics at university.
The planet is one of a class of “hot Jupiter” planets, which — unlike the planets in our own Solar System — have very tight orbits close to their stars. They are thought to have migrated inwards through interactions with another planet. Thus it is likely that Tom’s planet is not the only planet orbiting that star.
The planet does not yet have a name, though the International Astronomical Union has started a contest to name extra-solar planets. Tom is looking forward to making a suggestion for his planet.
The WASP collaboration (Wide Angle Search for Planets) is the UK’s leading team discovering planets, having been recognised with a Group Achievement Award by the Royal Astronomical Society. Keele University operates WASP-South, an array of cameras which surveys the Southern Hemisphere sky each clear night.
The WASP consortium also involves scientists from the Universities of Warwick, Cambridge and St. Andrews, and collaborates with scientists in Switzerland, France and Belgium. After Tom found the candidate planet, it was studied by astronomers at the University of Geneva and the University of Liege, to prove that it has the right size and mass to be a planet. A paper reporting an analysis of WASP-142b is being prepared.
Sunlight could whip up water to slake lunar settlers’ thirst
Sunrise at the Tycho crater, as seen by the Lunar Reconnaissance Orbiter (Image: NASA/Goddard Space Flight Center/Arizona State University)
Thirsty moon settlers might enjoy a drink with the help of the sun. At sunrise, its warmth drives water molecules from the lunar soil – ripe for harvest with the right know-how.
Since 2009, several lunar probes have found indirect evidence of abundant water on the moon by looking for hydrogen, since the element is present in water molecules. But no one wants the hassle of mining through the dusty surface to drink it.
The moon’s gravity is so low and its atmosphere so tenuous that water molecules in the ground turn directly to vapour when heated. Free to bounce around at near the speed of sound, they condense again when they get cold, piling up as frost where temperatures are low. The greatest build-up is at the dawn terminator: the region where the sun is just rising.
A lunar “day” is a full month long, so the water molecules have a lot of time to accumulate. Tim Livengood of NASA’s Goddard Space Flight Center in Greenbelt, Maryland wondered how much drinkable water you could collect if you set up a solar-powered distillery to catch the morning frost.
“When the sun rises – actually, when the surface rotates into sunlight – we just drop a clear plastic dome over our collecting surface and let the sun turn it back into vapour,” Livengood says. The vapour then frosts up the inside of the surface, where it can be harvested.
Using hydrogen measurements taken between 2009 and 2011 by NASA’sLunar Reconnaissance Orbiter (LRO), Livengood calculated that the frost build-up at the terminator would be just under a fifth of a millimetre thick – enough to yield about 190 millilitres of water per square metre per lunar day, with a suitable set-up. That could include a small sun-tracking shade to cast a permanent shadow, mimicking the terminator and allowing astronauts to collect frost all day long.
“The quantity of water is much less than what we could dig up at the lunar poles, but we get it with very little energy investment on our part,” Livengood says. “We just need to be patient.”
But Andrew Jordan of the University of New Hampshire in Durham thinks water isn’t the only possible explanation for the hydrogen peaks LRO observed in some regions.
“I would expect the amount of hydrogen to increase with depth,” he says. However, since the LRO observations are in line with hydrogen decreasing with depth, he is inclined to think something else is going on. It could be that hydrogen is leaking from localised sources, he says.
Livengood says it’s possible he is misinterpreting the LRO data, but he’s confident there is plenty of hydrogen at the surface, where previously scientists thought there was none.
“There is something going on here that was unanticipated, which means there is something new for us to learn about the world,” he says.
Journal reference: Icarus, DOI: 10.1016/j.icarus.2015.04.004
There’s Glass on Mars — Here’s Why It’s Important
An impact crater containing deposits of glass could hold clues for understanding life on Mars. Discovered by NASA’s Mars Reconnaissance Orbiter, the glass is believed to be the byproduct of the intense heat from a violent impact.
Glass in and of itself isn’t necessarily indicative of life — the surprise lies potentially lies within: in 2014, researchers discovered evidence of organic plant life entombed in glass found in Argentina from millions of years ago. “Glasses are potentially important for preserving biosignatures,” according to Brown University researcher Kevin Cannon.
Researchers hope that the same could hold true on Mars: that the glass deposits hold important biosignatures of ancient Martian life.
“The researchers’ analysis suggests glass deposits are relatively common impact features on Mars,” said Jim Green, director of NASA’s planetary science division. “These areas could be targets for future exploration as our robotic scientific explorers pave the way on the journey to Mars with humans in the 2030s.”
Conveniently, one of the glass-containing craters is located within close proximity to the Nili Fossae trough, which has already been identified as a possible landing site for NASA’s Mars 2020 rover mission. The mission aims to collect soil and rock samples that could potentially be returned to Earth and analyzed.