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The huge ocean sloshing beneath the ice shell of the Jupiter moon Europa may be intriguingly similar to the seas of Earth, a new study suggests. Scientists have generally thought that sulfate salts dominate Europa's subsurface ovean, which harbors about twice as much water as all of Earth's seas put together. But the Hubble Space Telescope has detected the likely presence of sodium chloride (NaCl) on Europa's frigid surface, the study reports.  The NaCl — the same stuff that makes up plain old table salt — is probably coming from the ocean, study team members said. And that's pretty exciting, given that the saltiness of Earth's oceans comes primarily from NaCl.  "We do need to revisit our understanding of Europa's surface composition, as well as its internal geochemistry," lead author Samantha Trumbo, of the California Institute of Technology in Pasadena, told Space.com.  "If this sodium chloride is really reflective of the internal composition,...

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SpaceX’s Crew Dragon capsule experienced an “anomaly” during a rocket test on Saturday that sent smoke drifting high over its launchpad at the Kennedy Space Center in Florida. Elon Musk and SpaceX have been short on details so far, but unconfirmed video footage shows the spacecraft being destroyed. The same Crew Dragon capsule completed a flawless flight to the International Space Station in March.The event raises concerns that SpaceX may not be able to fly humans to space for the first time this year, let alone hit their target launch date in July. Test malfunction The mishap took place as SpaceX was performing a static fire of their SuperDraco engines. That means the spacecraft was tethered and not meant to leave the launchpad. SuperDracos are directly attached to the crew capsule, and the large Falcon rockets that would actually launch the spacecraft into orbit were not in use. The SuperDracos’ job is to carry the crew capsule safely away from the...

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Mercury has a heart of iron; literally

Monday, April 22nd 2019 01:31 PM

Using sophisticated software to precisely analyse how Mercury’s gravity affected the trajectory of NASA’s MESSENGER spacecraft during multiple low-altitude orbits, researchers have been able to show the small planet must have a large, solid-iron inner core measuring some 2,000 kilometres (1,260 miles) across, almost as large as Earth’s. Including its molten metal outer layer, Mercury’s metallic core fills nearly 85 percent of the planet’s volume, huge compared to the cores of the solar systems other terrestrial planets. “Mercury’s interior is still active, due to the molten core that powers the planet’s weak magnetic field, relative to Earth’s,” said Antonio Genova, an assistant professor at Sapienza University of Rome who led the research. “Mercury’s interior has cooled more rapidly than our planet’s. Mercury may help us predict how Earth’s magnetic field will change as the core cools.” To det...

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The Sky This Week from April 19 to 28

Friday, April 19th 2019 02:02 PM

Friday, April 19Full Moon arrived at 7:12 a.m. EDT this morning, but it still looks completely illuminated tonight. It rises in the east about a half-hour after sunset and climbs well above the southeastern horizon by late evening. The Moon spends the evening in the northwestern corner of the constellation Libra the Scales.Saturday, April 20Venus pokes above the eastern horizon about an hour before sunrise. The brilliant planet dominates the predawn sky as the rosy glow heralding the Sun’s arrival grows brighter. Venus shines at magnitude –3.9, some four times brighter than the second-brightest planet, Jupiter. When viewed through a telescope, the inner world shows a disk that spans 12" and appears 86 percent lit.Sunday, April 21Mars continues to add its ruby-red glow to Taurus the Bull this week. Shining at magnitude 1.6, the Red Planet appears slightly fainter than the constellation’s brightest star, ruddy 1st-magnitude Aldebaran. The planet lies nearly 30° ab...

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Nearby asteroids reveal sizes of distant stars

Thursday, April 18th 2019 10:33 AM

Stars in the night sky appear as tiny points of light because they are too far away for your eyes to resolve. But even through powerful telescopes, stars still appear as mere points because they are too small to see their true physical size at vast distances. Now, a group of astronomers from over 20 different institutions has found a way to combine a unique telescope array with passing asteroids to measure the diameter of two distant stars, including the smallest star directly measured to date at just over twice the size of our Sun. Their work appeared April 15 in Nature Astronomy. And using this new information, astronomers can better refine their picture of the properties and life cycles of stars, which are the building blocks that make up our galaxy and every other galaxy in the universe. How to measure a star To measure the size of a star, the collaboration used events called occultations. An occultation occurs when one object — such as an asteroid or plane...

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Third planet found hiding in ‘Tatooine’ star system

Wednesday, April 17th 2019 12:01 PM

Like the planet Tatooine from Star Wars, two suns — one bright, one dim and red— rise over the horizon of Kepler 47d. But unlike dry and sandy Tatooine, this planet’s surface is gassy and indistinct. The system also holds two smaller planets; one planet closer to the double suns, and one farther out. Both lack a solid surface. If you visited in a spaceship, all the planets would be easy to spot because they’re packed, along with their stars, into a space smaller than Earth’s orbit around the Sun. This week, astronomers on Earth announced that they’d only just now discovered the middle planet, making an already noteworthy system even more unique. In fact, Kepler 47 is the only known multi-planet system orbiting a binary star. And it just solidified that place of honor by revealing a third planet hiding between the two already known planets. This tightly packed system has little in common with our solar system, and astronomers...

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Astronomers have discovered a third planet in the Kepler-47 system, securing the system's title as the most interesting of the binary-star worlds. Using data from NASA's Kepler space telescope, a team of researchers, led by astronomers at San Diego State University, detected the new Neptune-to-Saturn-size planet orbiting between two previously known planets. With its three planets orbiting two suns, Kepler-47 is the only known multi-planet circumbinary system. Circumbinary planets are those that orbit two stars. The planets in the Kepler-47 system were detected via the "transit method." If the orbital plane of the planet is aligned edge-on as seen from Earth, the planet can pass in front of the host stars, leading to a measurable decrease in the observed brightness. The new planet, dubbed Kepler-47d, was not detected earlier due to weak transit signals. As is common with circumbinary planets, the alignment of the orbital planes of the planets change with t...

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The first-ever photo of a black hole was released on Wednesday, giving a physical form to an astronomical phenomenon that had previously only been hypothesized. Imaging a black hole for the first time was a major accomplishment — and an emotionally moving one for the scientists involved — but perhaps the most important part of this discovery isn’t what it revealed but what it confirmed.   In a series of six papers published Wednesday in The Astrophysical Journal Letters, over 200 scientists involved in the Event Horizon Telescope collaboration describe how they collected enough light from the black hole at the center of the galaxy Messier 87 to reveal humanity’s first look at a black hole. The image of the black hole is just one artifact of this immense project. Through the image, astronomers got their first close-up glimpse at an astronomical phenomenon whose existence was predicted a century ago, allowing them to test their pre...

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After a nearly seven-week adventure since its launch, the Israeli Beresheet spacecraftwill attempt make history today and touch down on the surface of the Moon at 10:25 p.m. Israel time (2:25 p.m. Central). It’s a monumental undertaking and if it succeeds, Beresheet and its creators will join the select ranks of those who have safely landed on the Moon – thus far only the United States, China, and the former Soviet Union. NASA and its Deep Space Network are aiding the mission in tracking and communications. Beresheet plans to touch down in Mare Serenitatis, not far from NASA’s Apollo 15 and 17 landing sites, and is expected to send back pictures of its descent and arrival on the Moon. It will operate there for only two to three days before the sunlight grows too intense and overheats the tiny spacecraft, but that will be enough to cement its place in history. Fashionably late SpaceIL is a private company that built and operates the spacecra...

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On Wednesday, astronomers revealed the first image ever taken of a black hole, bringing a dramatic conclusion to a decades-long effort. The iconic image offers humanity its first glimpse at the gas and debris that swirl around its event horizon, the point beyond which material disappears forever. A favorite object of science fiction has finally been made real on screen.Their target was a nearby galaxy dubbed M87 and its supermassive black hole, which packs the mass of six and half billion suns. Despite its size, the black hole is so far from Earth – 53 million light-years – that capturing the image took a telescope the size of the planet.This monumental accomplishment was only possible thanks to the Event Horizon Telescope (EHT). The image data was taken back in 2017 but scientists have spent two years piecing it together. That’s because EHT is made of up eight independent observatories that are scattered across the globe, cooperating together to act as one enormous...

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