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Scientists think that they've spotted a rare, Jupiter-size black hole casually strolling through the Milky Way galaxy.
Of course, scientists can't see any black holes directly — but new research tracking a celestial cloud structure saw strange behavior that may have been caused by just such an invisible object. That data came courtesy of the Atacama Large Millimeter/submillimeter Array (ALMA), a set of 66 telescopes scattered across the Atacama Desert in northern Chile.
"When I checked the ALMA data for the first time, I was really excited because the observed gas showed obvious orbital motions, which strongly suggest an invisible massive object lurking," lead author Shunya Takekawa, a physicist at the National Astronomical Observatory of Japan, told New Scientist.
Takekawa and his colleagues were using ALMA to study two gas clouds, which the team nicknamed Balloon and Stream for their shapes, during a two-day period in May 2018. During that time, they watched the gas moving strangely, seeming to spin around a center.
That movement allowed the team to calculate that 30,000 times the mass of our sun was packed into an object the size of Jupiter at the center of the movement. Those characteristics, combined with the lack of light coming from the location, suggest that the culprit is medium size for a black hole.
Scientists think tiny black holes and supermassive black holes are pretty common, but that there aren't a whole lot of medium-size black holes. Astronomers believe they've spotted two other black holes in this size range near the heart of the Milky Way. All three, if future observations continue to see evidence for them, may be escapees from the giant black hole at our galaxy's center.
The research is described in an article posted to the preprint server arXiv.org on Dec. 27.
Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us @Spacedotcom and Facebook. Original article on Space.com.
The Mars Science Laboratory and its rover centerpiece, Curiosity, is the most ambitious Mars mission yet flown by NASA. The rover landed on Mars in 2012 with a primary mission to find out if Mars is, or was, suitable for life. Another objective is to learn more about the Red Planet's environment.
In March 2018, it celebrated 2,000 sols (Mars days) on the planet, making its way from Gale Crater to Aeolis Mons (colloquially called Mount Sharp), where it has looked at geological information embedded in the mountain's layers. Along the way, it also has found extensive evidence of past water and geological change.
[For the latest news about the mission, follow Space.com's Mars Science Lab Coverage.] As big as an SUV
One thing that makes Curiosity stand out is its sheer size: Curiosity is about the size of a small SUV. It is 9 feet 10 inches long by 9 feet 1 inch wide (3 m by 2.8 m) and about 7 feet high (2.1 m). It weighs 2,000 lbs. (900 kilograms). Curiosity's wheels have a 20-inch (50.8 cm) diameter.
Engineers at NASA's Jet Propulsion Laboratory designed the rover to roll over obstacles up to 25 inches (65 centimeters) high and to travel about 660 feet (200 m) per day. The rover's power comes from a multi-mission radioisotope thermoelectric generator, which produces electricity from the heat of plutonium-238's radioactive decay. Science goals
According to NASA, Curiosity has four main science goals in support of the agency's Mars exploration program:
Determine whether life ever arose on Mars. Characterize the climate of Mars. Characterize the geology of Mars. Prepare for human exploration.
The goals are closely interlinked. For example, understanding the current climate of Mars will also help determine whether humans can safely explore its surface. Studying the geology of Mars will help scientists better understand if the region near Curiosity's landing site was habitable. To assist with better meeting these large goals, NASA broke down the science goals into eight smaller objectives, ranging from biology to geology to planetary processes.
In support of the science, Curiosity has a suite of instruments on board to better examine the environment. This includes:
Cameras that can take pictures of the landscape or of minerals close-up: Mast Camera (Mastcam), Mars Hand Lens Imager (MAHLI) and Mars Descent Imager (MARDI). Spectrometers to better characterize the composition of minerals on the Martian surface: Alpha Particle X-Ray Spectrometer (APXS), Chemistry &&Camera (ChemCam), Chemistry &&Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument (CheMin), and Sample Analysis at Mars (SAM) Instrument Suite. Radiation detectors to get a sense of how much radiation bathes the surface, which helps scientists understand if humans can explore there – and if microbes could survive there. These are Radiation Assessment Detector (RAD) and Dynamic Albedo of Neutrons (DAN). Environmental sensors to look at the current weather. This is the Rover Environmental Monitoring Station (REMS). An atmospheric sensor that was primarily used during landing, called Mars Science Laboratory Entry Descent and Landing Instrument (MEDLI).
A complicated landing
The spacecraft launched from Cape Canaveral, Florida, on Nov. 26, 2011, and arrived on Mars on Aug. 6, 2012, after a daring landing sequence that NASA dubbed "Seven Minutes of Terror." Because of Curiosity's weight, NASA determined that the past method of using a rolling method with land bags would probably not work. Instead, the rover went through an extremely complicated sequence of maneuvers to land.
From a fiery entry into the atmosphere, a supersonic parachute needed to deploy to slow the spacecraft. NASA officials said the parachute would need to withstand 65,000 lbs. (29,480 kg) to break the spacecraft's fall to the surface.
Under the parachute, MSL let go of the bottom of its heat shield so that it could get a radar fix on the surface and figure out its altitude. The parachute could only slow MSL to 200 mph (322 kph), far too fast for landing. To solve the problem, engineers designed the assembly to cut off the parachute, and use rockets for the final part of the landing sequence.
About 60 feet (18 m) above the surface, MSL's "skycrane" deployed. The landing assembly dangled the rover below the rockets using a 20-foot (6 m) tether. Falling at 1.5 mph (2.4 kph), MSL gently touched the ground in Gale Crater about the same moment the skycrane severed the link and flew away, crashing into the surface.
NASA personnel tensely watched the rover's descent on live television. When they received confirmation that Curiosity was safe, engineers pumped fists and jumped up and down in jubilation.
News of the landing spread through traditional outlets, such as newspapers and television, as well as social media, such as Twitter and Facebook. One engineer became famous because of the Mohawk he sported on landing day. Tools for finding clue
Sol 40: Instrument Context Camera (ICC)
NASA's InSight Mars lander acquired this image of the area in front of the lander using its lander-mounted, Instrument Context Camera (ICC).
This image was acquired on January 6, 2019, Sol 40 of the InSight mission where the local mean solar time for the image exposures was 15:17:11.458 PM. Each ICC image has a field of view of 124 x 124 degrees.
Image Credit: NASA/JPL-Caltech
Sounds of Mars: NASA’s InSight Senses Martian Wind
Listen to Martian wind blow across NASA’s InSight lander. The spacecraft’s seismometer and air pressure sensor picked up vibrations from 10-15 mph (16-24 kph) winds as they blew across Mars’ Elysium Planitia on Dec. 1, 2018. The seismometer readings are in the range of human hearing, but are nearly all bass and difficult to hear on laptop speakers and mobile devices. We provide the original audio and a version pitched up by two octaves to make them audible on mobile devices. Playback is suggested on a sound system with a subwoofer or through headphones. Readings from the air pressure sensor have been sped up by a factor of 100 times to make them audible. For full-length uncompressed .wav files, visit NASA.gov/sounds For more about the InSight mission, visit mars.nasa.gov/insight .
Credit: NASA/JPL-Caltech/CNES/IPGP/Imperial College/Cornell
For more than two decades, scientists have wondered whether extraterrestrial life may be flourishing deep below the icy coatings boasted by moons in our outer solar system.
Spacecraft like the Galileo mission to Jupiter and the Cassini mission to Saturn have stumbled on evidence that some of their moons hide global oceans, warmed by the pull of the giant planet they orbit. And oceanic explorers much closer to home have discovered dynamic communities living in darkness around geologic features on the ocean floor. Combine the two and it's easy to be carried away with dreams of alien seafloors teeming with microbes. But new research is looking deeper, into the rock itself, and suggesting that these worlds may be dead inside — not just biologically, but geologically as well.
"We were wondering, what would it look like if you were in a submarine and you were able to fly over the surface of the ocean floor on [Jupiter's moon] Europa," lead author Paul Byrne, a planetary geologist at North Carolina State University told Space.com last month at the annual conference of the American Geophysical Union in Washington. [Photos: Europa, Mysterious Icy Moon of Jupiter]
These are the seafloors where astrobiologists have hoped to find heated, mineral-packed seawater spitting out into the ocean, like hydrothermal vents and black smokers on Earth. In our oceans, those features support bustling communities centered on microbes ("crawlies," as Byrne calls them) that can feed themselves on chemicals produced where hot rock and seawater continuously mix. If similar structures are found on alien ocean worlds, the prospect of finding life on worlds far from the sun becomes just a little more plausible.
"I was hoping we could characterize what the chain of volcanoes would look like, what the rift zones would look like — and then we were like, 'Well, I don't think they're going to be there,'" Byrne said.
Rock solid
To reach that conclusion, the team focused on the rock itself, determining how much force would be necessary to break the rock in two ways we see on Earth: normal faults, which occur when rock is pulled apart, and thrust faults, which occur when rock is pushed together and which require more force to produce. The more force required to break rock, the less geological activity is happening — and that means less of the interactions between fresh rock and alien seawater that could theoretically support life.
Byrne and his colleagues focused on four ocean worlds: Jupiter's moons Europa and Ganymede and Saturn's Enceladus and Titan. For each of these worlds, the team calculated the strength of the rock. While there are plenty of questions we can't yet answer about these worlds, it turns out that rock strength calculations — which are commonly made on Earth for mining operations — are pretty feasible.
Those calculations are based on the thickness of the cold, solid rock layer, which rests on top of a warmer, mushy layer that can't break. An analogy may help. "Think of like a Milky Way bar or a Mars bar, it's where the chocolate and caramel touch," Byrne said. "That depth, you can treat that as the thickness of the brittle, rigid layer." The thicker it is, the harder it is to break.
Then the team added other values, like the body's gravity at a set depth and the weight of water and ice on top of the moon's rocky surface. Even when they included a range of plausible values for unknown inputs, the final calculations were in the same general range for each moon. [Photos: Enceladus, Saturn's Cold, Bright Moon]
Byrne said those initial results, which he was presenting at the conference, suggest that the rock is so strong that there's no force we know of on these moons powerful enough to regularly crack it. That's because of the sheer weight of the water and ice sitting above the rock. "When it actually comes to understanding how strong the rock is, it's pretty strong, and it's pretty strong because even though the gravity's pretty low there's a lot of water on top of it," Byrne said.
Each moon the team studied showed a different calculated rock strength, but the results aren't particularly promising for geological showstoppers or would-be alien life. "For Europa, it seems really, really hard to make any fractures or faults, and then once you look at Titan and Ganymede, these numbers are stupid high, really, nothing's happening at all on those worlds," Byrne said.
Enceladus' rock strength numbers aren't as grim, since this moon is much smaller than the other three, which reduces the weight of the water and ice above its rocky surface. The picture also looks a little different at Enceladus because its rocky core is more porous. If those pores happen to line up, they could carry water deep into the moon. "It's within the realms of plausibility that Enceladus might actually be wet and soggy all the way through," Byrne said.
And unlike for the other moons, scientists do have evidence suggesting that rock and water are interacting at Enceladus, thanks to Cassini's flight through seawater plumes shooting through the icy crust and into space, which identified organic compounds. "That's quite encouraging," Byrne said. "It's hard to explain that it's not rock and water touching."
Billiard ball worlds
If the rock at all these seafloors is too strong to be broken regularly, Byrne said, it's difficult to imagine much could be happening down there. On Earth, two major factors shaping the seafloor are soil washing off the continents and the bodies of sea creatures sinking to decay, and neither seems likely on these ocean worlds. Spacecraft haven't seen scars left behind by any impacts that seem large enough to plausibly make a recent dent on the seafloor. And based on his calculations, the rock is too strong to allow the moons to shrink like the planet Mercury or to sport volcanic chains or rift zones.
All that means the submarine ride suddenly looks awfully boring. "Basically, it becomes a list of things there won't be," Byrne said. "It'll look like a billiard ball, it'll be a weird smooth planet. It'll be a new type of rocky world in our solar system." [Photos of Ganymede, Jupiter's Largest Moon]
He emphasized that these aren't final results. The team is still seeing how other scientists respond to the calculations, and the research isn't published yet. And it will likely be decades before scientists could gather the data they might need to really test the idea — which would require seismometers on these alien seafloors. Humans are just now beginning to get their first good seismometer data from another planet, thanks to the InSight lander on Mars.
Byrne is philosophical about his team's calculations and how dramatically they seem to undermine what scientists have expected of these worlds. "If we're wrong, fine, that's how science works, that's grand, we'll take it, we'll be happy about it," he said.
In fact, he said he's a little sad about his own team's findings. "It would be great if we found interesting stuff, because these worlds are cool and maybe there's life there," Byrne said. "But if we're right, it means we do need to reconsider these worlds as habitable destinations or destinations for exploring habitability."
Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us @Spacedotcom and Facebook. Original article on Space.com.a
NASA Mars Report: Dec. 20, 2018
NASA’s InSight has been busy. After landing on the Red Planet, the mission sent home pictures and sound, then placed its first instrument on the planet's surface. Plus, find out what the Curiosity rover has been up to. For more Mars exploration updates, visit https://mars.nasa.gov .
The sort of small, young, active stars that have become most exciting to astronomers looking for exoplanets may actually push away precisely what could be necessary to carry water to those planets — leaving them too dry to support life.
That's the suggestion of one recent study of just such a star, in the class astronomers call M dwarfs. The lead researcher presented an update about the project at a conference, where she stressed that the research was ongoing — but that it posed intriguing challenges to astronomers' ideas about where to look for life.
"The show's going to be basically over certainly by 30 million years," Carol Grady, a scientist at Eureka Scientific, a company that hires and facilitates scientists applying for funding and instrument use as principal investigators, said during a news conference held Tuesday (Jan. 8) at the annual conference of the American Astronomical Society. "What this suggests is that processes which depend on disk survival may be inhibited in systems around young M stars, and this includes the delivery of water and organics to terrestrial-mass planets in the habitable zone." [7 Ways to Discover Alien Planets]
Grady and her colleagues came to this conclusion by studying Hubble Space Telescope images of the debris disk surrounding a star called AU Microscopii taken between 2010 and 2018. The star is fairly close to us, at less than 32 light-years away, and scientists know that it's about 24 million years old. As far as scientists know so far, it sports one planet, which orbits once every month or so.
The images the team studied rely on a coronagraph, which blocks out the light of the star itself so that the disk surrounding it isn't outshone. "We basically put a fist over the star," Grady said. "It's exactly like walking down the beach at sunset when you're trying to see — Is that your friend who's got the ice creams you wanted? — so you just stick your hand out and block the light and improve your contrast."
As they were studying these images, the team noticed that they could see the same blob-like feature in the disk surrounding , but that it seemed to migrate outward over time. Then they saw another, and another. They've identified a total of six such structures, which in our solar system would stretch from the sun out to Jupiter.
Those blobs are concerning because they seem to be pushing material out of the debris disk around the planet. It's that debris field that a planet born dry would need to rely on to carry water and other life-fostering chemicals to it during bombardments. (This is how Earth got the water in your body, for example.)
And according to the progress of the blobs Grady and her colleagues tracked, around AU Microscopii, that could wipe out the debris disk in about 1.5 million more years. That means the system would have had such cosmic deliveries for less than 30 million years all told — probably not long enough to build up a particularly wet planet and give life time to evolve.
The new research is far from the first challenge to the idea that planets orbiting close to small stars might be promising places to look for life. While these planets are easy to identify using the most productive technique, the transit method, and they seem to be the right temperature to hold liquid water, astronomers have pointed to plenty of other factors that could influence habitability, like the harsh flares of radiation these stars produce. The loss of debris disks could be just one more factor that depreciates these stellar neighborhoods.
But what's truly stumping the team working on the new research is precisely what those blobs actually are. "We do not know the mechanism responsible for ejecting these things," Grady said. "[We've considered] a large number of mechanisms that have died various messy deaths." For example, they thought the phenomenon might be caused by a distant planet, but that didn't seem to match the geometry of the situation.
Grady said she and her colleagues are hoping to win more telescope time to chip away at the continuing mystery, but that it's a logistically challenging phenomenon to tackle. "Astronomers tend to like projects with beginnings and ends, and the problem is, what we're finding is phenomena which take longer."
Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels. Follow us @Spacedotcom and Facebook. Original article on Space.com.
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