Tuesday, November 7, 2017

The Most Powerful Magnets in the Universe Are Collapsed Stars

When a large star dies, sometimes it becomes a neutron star, a tiny, 12 mile across ball that's made almost entirely out of neutrons. These dead stars are incredibly dense, and spin incredibly fast. Just one thimbleful of neutron star would weigh 100 million tons. Magnetars are a variation of neutron stars, and they somehow manage to be even scarier. Neutron stars already have extremely strong magnetic fields--about 2 trillion times more powerful than Earth's. Yet magnetars have magnetic fields 1,000 times stronger than that. Yeah, that's a pretty intense field. Magnetars are not just insanely powerful--they're also very, very dangerous. If you were a mere 1,000 kilometers from a magnetar, your entire body would dissolve as the magnetic field rearranged the sequence of atoms in your body. 

In addition to their terrifying magnetic powers, magnetars also have something called starquakes, which function similarly to earthquakes here on Earth--except with much more intense results. A crack in the crust of a magnetar is responsible for the brightest light we've ever observed from space. And if a magnetar was closer to us, like 10 light years away, and blasted us with the radiation from a starquake, it would destroy our ozone layer and probably kill all life on Earth.

But don't worry--thankfully, there aren't any magnetars near Earth. The closest one is about 9,000 light years away. Let's pray that it stays that way.

Tuesday, October 31, 2017

Three New Gas Giants May Provide Hint Into Major Astronomical Mystery

European astronomers with the Super Wide Angle Search for Planets (SuperWASP) consortium of planet hunters have detected three new gas giant alien worlds.The SuperWASP is an international effort to use the Roque de los Muchachos Observatory in Spain and the South African Astronomical Observatory to discover exoplanets. Both observatories are equipped with eight wide-angle cameras that monitor the sky for planetary transit events (when planets pass in front of their stars, allowing them to be imaged by human telescopes). The three planets were discovered orbiting three stars also discovered by the SuperWASP program: WASP-151, WASP-153 and WASP-156. "In this paper, we report the discovery of three transiting exoplanets by the SuperWASP survey and the SOPHIE spectrograph with mass and radius determined with a precision better than 15 percent," wrote the astronomers, led by a team out of the University of Porto in Portugal.

Two of the planets are "hot Saturns," large but low-density gas giants that are very close to their stars. The larger of the two, WASP-153b, has a radius 1.86 times that of Saturn and is 1.3 times as dense. The smaller hot Saturn, WASP-151b, is 1.36 times larger than Saturn and is 1.03 times as dense. Both of them have orbital periods of less than a week.

Meanwhile, the third planet is a "super-Neptune:" a planet appreciably bigger than Neptune (2.5 times more massive in this case) but smaller than Saturn, which is about five times more massive than Neptune. This third planet, WASP-156b, only needs 3.83 days to complete a revolution around its star.

This third find is the exciting one to astronomers, as shockingly few super-Neptunes have been discovered — a dearth named the so-called "Neptunian Desert." Many terrestrial planets (like Earth and Venus), gas giants (like Jupiter and Saturn), and super-Earths (like Uranus and Neptune) have been discovered. Meanwhile 156b is only the ninth-ever super-Neptune to be found of the thousand-plus exoplanets confirmed — and nobody is sure why.

"These three planets also lie close to (WASP-151b and WASP-153b) or below (WASP-156b) the upper boundary of the Neptunian desert. (…) While a detailed analysis of the origin of the Neptunian desert is beyond the scope of this paper, it is still interesting to look into the similarities and differences between WASP-156b and WASP-151b/WASP-153b since they might provide useful hints on the nature of this desert," the paper reads.

Monday, October 30, 2017

SpaceX to Launch Korean Communications Satellite Today: Watch It Live

SpaceX aims to pull off another launch-and-landing double play today (Oct. 30), and you can watch all the spaceflight action live. A SpaceX two-stage Falcon 9 rocket is scheduled to launch the KoreaSat 5A communications satellite at 3:34 p.m. EDT (1934 GMT) today from Florida's Cape Canaveral Air Force Station. You can courtesy of SpaceX, or directly via the company at http://www.spacex.com/webcast. If all goes according to plan, the booster's first stage will return to Earth for a soft landing less than 10 minutes after liftoff, settling vertically onto a SpaceX "drone ship" stationed off the Florida coast. Such landings are part of SpaceX's plan to develop fully and rapidly reusable rockets and space vehicles, a key priority for the company and its billionaire founder and CEO, Elon Musk. To date, SpaceX has aced 18 Falcon 9 touchdowns and re-launched landed boosters on three different occasions.

SpaceX has also re-flown a Dragon cargo capsule once and aims to do so again on its next resupply run to the International Space Station for NASA, which will launch no earlier than December.

KoreaSat 5A is owned by the South Korean company KTSat. The satellite will provide TV and other communications services to people in South Korea, Japan and Southeast Asia, according to the company's website. The satellite will also aid maritime communications from East Africa to East Asia.

KoreaSat 5A will replace KoreaSat 5, which launched in 2006.

Friday, October 27, 2017

We may have just seen the first comet from another solar system

The solar system may be hosting a visitor from the stars. A newly discovered comet is screaming away from Earth, and based on its weird orbital trajectory astronomers think it might be the first comet ever observed that came from interstellar space. A sky-surveying telescope in Hawaii spotted the fast-moving object, now called C/2017 U1, on 18 October, after its closest approach to the sun. During the next week, astronomers made 34 separate observations of the object and found it has a strange trajectory that is at an angle to the orbits of the planets and does not circle the sun. Now, astronomers are hoping more skywatchers will take a look and pin down whether it’s from our neighborhood or an interloper from beyond. Most comets follow ellipse-shaped orbits around the sun, swooping in from the distant Oort Cloud to kiss the inner solar system before heading back out again. This one, by contrast, will never return. Its orbital path suggests it sailed in from the direction of the constellation Lyra above the relatively flat plane of the solar system, looped around the sun, and is headed back out for eternity.

Lyra is near the direction the sun is moving within the Milky Way, says Luke Dones at the Southwest Research Institute in Boulder, Colorado. “That’s exactly what you’d expect; there should be more interstellar comets coming from the direction the sun is heading toward,” he says.
Just popping in

“It’s coming from very far away, but we can’t actually backtrack how far away it started. It could be that it’s coming from outside the solar system, but it’s really hard to tell,” says Simon Porter, also at the Southwest Research Institute. Further observations in the next couple weeks will make the picture clearer.

What’s more, a comet on such an extreme path doesn’t necessarily have to come from interstellar space. “It could have interacted with Jupiter or another planet in such a way that changed its orbit,” says Maria Womack at the University of South Florida in Tampa.

The comet’s origins are hard to pin down in part because of the nature of comets. “When you think of photos of comets, they’re a fuzzy blob. People have to make determinations of where they think the center is. Someone who is at the telescope has to make a call,” Womack says.

This necessary guesswork makes the measurements less precise, so astronomers want lots of observations before they’ll be convinced the comet really is from beyond our solar system, she adds.

Luckily, there are plenty of opportunities left to take a peek. The comet should be visible in powerful telescopes for at least another couple weeks, allowing amateurs and professionals alike to survey the icy visitor and determine its history.

Wednesday, June 28, 2017

Success of Gravity-Wave Satellite Paves Way for 3-Craft Mission

Europe’s gravitational-wave hunters are celebrating. On July 1, a satellite will wrap up its mission to test technology for the pioneering quest to measure gravitational ripples in the stillness of space. Over the past year, the craft has performed much better than many had hoped. That success has convinced the European Space Agency (ESA) to give the go-ahead to a full-scale version able to sense cataclysmic events that can’t be felt on Earth. The LISA Pathfinder mission, launched in late 2015, beat its precision target by a factor of 1,000 and quieted critics who have doubted its potential, says project scientist Paul McNamara, an astrophysicist at ESA in Noordwijk, the Netherlands. “This is not the impossible task that some people believed it was.” Currently set to fly in 2034, the full-scale Laser Interferometer Space Antenna (LISA) will be the space analogue of the Laser Interfero-meter Gravitational-Wave Observatory (LIGO), two machines in the United States—each with a pair of 4-kilometre-long arms—that first detected the ripples by ‘hearing’ the merger of two black holes.

LISA Pathfinder—shown before being encapsulated into a rocket for launch—allowed scientists to test technology for detecting gravitational waves. 

 LISA’s three probes will fly in a triangle, millions of kilometres apart, making the mission sensitive to much longer gravitational waves, such as the ripples produced by the collisions of even larger black holes.

The mission will bounce laser beams between the three LISA craft—or, more precisely, between test masses suspended in a vacuum inside each satellite. Taking advantage of the vibration-free conditions of space, it will measure tiny variations in the distances between the test masses that reveal the passage of space-warping gravitational waves.

LISA Pathfinder’s goal was to show that such variations could be measured in zero gravity and with a precision of one pico-metre, or one-billionth of a millimetre. High-precision thrusters adjusted Pathfinder’s route so that it would closely follow the gravitational free fall of two test masses inside the craft and not interfere with their orbit. At the same time, the probe bounced a laser beam between the two masses—a pair of 2-kilogram cubes made of a gold and platinum alloy—and measured fluctuations in their separation.

The €400-million (US$447-million) probe was declared a success in February 2016, two weeks after LIGO announced its first detection. Pathfinder did not detect gravitational waves—which would not have appreciable effects over the short distance inside the probe—but it showed that it could detect motions 100 times smaller than the pico-metre requirement. Since then, the experiment’s performance has improved by another order of magnitude (M. Armano et al. Phys. Rev. Lett. 118,171101; 2017).

By early June this year, LISA Pathfinder had almost run out of thruster fuel, and mission control used what was left to nudge the spacecraft out of its operating orbit and into its final orbit around the Sun. On 1 July, Pathfinder will stop collecting data, and the spacecraft will be put to sleep for good on 18 July.

Pathfinder was “a triumph”, says William Klipstein, a physicist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who works on LISA development but was not involved in ESA’s Pathfinder mission. Its performance “removes the last major technical barrier for proceeding with a long-planned ESA-led gravitational-wave mission”, he says.

In a unanimous decision on June 20, ESA’s Science Programme Committee officially selected LISA as the third of the agency’s large, or €1-billion-class, mission in its current science programme. The approval was long-awaited but had been in little doubt after Pathfinder’s success and LIGO’s gravitational-wave discoveries, says Karsten Danzmann, a director of the Max Planck Institute for Gravitational Physics in Hanover, Germany, and Pathfinder’s co-principal investigator.

The decision is not final, but it means that industrial partners will now be involved in detailed design and cost projections. Once those are finished, ESA will decide whether to ‘adopt’ the mission and commit the funding to build it. The United States—which was an equal partner in the mission until 2011, when it reduced its participation to save costs—is expected to provide important components.

ESA has chosen two other large missions to go ahead before LISA—one to the moons of Jupiter, slated to launch in 2022, and an X-ray observatory for 2028. This puts LISA on schedule to be launched in 2034. But Pathfinder principal investigator Stefano Vitale, a physicist at the University of Trento in Italy, and others hope that its schedule can be accelerated. ESA’s call for proposals to lead the gravitational-wave observatory—won by Vitale’s team—was put out in late 2016, instead of late 2019 as the agency had planned. Vitale and other gravitational-wave researchers hope the agency will push the launch date forward so that LISA can start sending back data before too many of the current key researchers have retired.