Jupiter moon Europa spouting water

This video says about itself:

26 September 2016

NASA has announced that a team using the Hubble Space Telescope has spotted possible water vapor plumes on Jupiter’s moon Europa.

From Science News:

Europa spouting off again

Hubble images of plumes on Jupiter’s icy moon revive talk of hidden ocean

By Christopher Crockett

5:18pm, September 26, 2016

Jupiter’s moon Europa might once again be venting water into space, further supporting the idea that an ocean hides beneath its thick shell of ice, researchers reported September 26 at a news conference.

Plumes erupting from the moon’s surface, silhouetted against background light from Jupiter, appear in several images taken by the Hubble Space Telescope in early 2014. The geysers — presumably of water vapor or ice particles — showed up in the same location as an eruption captured by Hubble in 2012 (SN: 1/25/14, p. 6). The eruptions also appear to be intermittent, appearing in only three out of 10 images. Material hovering over the moon’s southern hemisphere and absorbing ultraviolet light coming from Jupiter made the plumes visible.

“The plumes are a sign that we may be able to explore the ocean without having to drill through unknown miles of ice,” said William Sparks, an astronomer at the Space Telescope Science Institute in Baltimore. “We presume it to be water or ice particles because that’s what Europa is made of and those molecules do absorb at the wavelengths we observed,” he said. Future spacecraft could plow through the plumes and sample the water to better understand its chemistry and look for by-products of life.

First ever failed supernova discovered?

This video says about itself:

Hydrogen River Between Galaxies Breaks the Rules | Space News

28 February 2014

Scientists using the Green Bank Telescope have observed what they describe as a river of neutral hydrogen streaming into the Galaxy NGC 6946. The researchers conclude that this tenuous filament of gas is providing the necessary fuel for the high rate of star formation in the spiral galaxy.

From Science News:

Vanished star may be first known failed supernova

Despite no signs of massive explosion, black hole now marks stellar grave

By Christopher Crockett

6:00am, September 20, 2016

A star that mysteriously disappeared might be the first confirmed case of a failed supernova, a star that tried to explode but couldn’t finish the job. A newborn black hole appears to have been left behind to snack on the star’s remains.

In 2009, a star in the galaxy NGC 6946 flared up over several months to become over 1 million times as bright as the sun. Then, it seemed to vanish. While the star could just be hiding behind a wall of dust, new observations with the Hubble Space Telescope, reported online September 6 at arXiv.org, strongly suggest that the star did not survive. A faint trickle of infrared light, however, emanates from where the star used to be. The remnant glow probably comes from debris falling onto a black hole that formed when the star died, write Caltech astronomer Scott Adams and colleagues.

Black holes are typically thought to form in the aftermath of a supernova, the explosive death of a massive star. But multiple lines of evidence have recently hinted that not all heavyweights go out with a bang. Some stars might skip the supernova and collapse into a black hole. Until now, though, evidence that this happens has been either spotty or indirect.

“This is the first really solid observational evidence for a failed supernova,” says Elizabeth Lovegrove, an astronomer at the University of California, Santa Cruz. “Some supernovas really do fail and this is what they look like.”

This attempt at a supernova, first observed with the Large Binocular Telescope in Arizona, occurred about 19 million light-years away in the constellation Cygnus. Only one other known star — a yellow supergiant that faded away in 2010 — is suspected to be a failed supernova, though there’s not enough data to say for certain.

When a star at least eight times as heavy as the sun runs out of thermonuclear fuel, it can no longer support its own weight. Gas crashes down on the star’s core, bounces and sends a shock wave racing back toward the surface that tears the star apart. Some stars might be so massive that the shock wave doesn’t have enough oomph to push against the onrush of collapsing star stuff. The shock fizzles, the supernova fails and the core gathers enough mass to collapse into a black hole, possibly taking the rest of the star down with it.

If the dying star is a red supergiant — a ruddy orb that can be over 1,000 times as wide as the sun — it might give a signal before vanishing. As the core collapses, it releases an enormous amount of gravitational energy. A second shock wave ripples up through the star — not powerful enough for an explosion, but enough to burp off the loosely held outer layers of the supergiant and expose the feeding black hole.

That’s exactly what Adams and colleagues think they saw. Hubble images from before 2009 reveal a star about 25 to 30 times as massive as the sun sitting where the flash of light came from. The star doesn’t show up in images taken since the eruption. Neither the brightness of the flash, the rate at which the brightness evolved nor the amount of light coming from there now fully matches other types of stellar incidents, such as a collision between a pair of stars or the violent outbursts that accompany some aging supermassive stars.

If the star did give birth to a black hole, X-rays may be radiating from debris spiraling down its gravitational throat. Adams and collaborators are waiting on observations from the space-based Chandra X-ray Observatory to check that idea. They also continue to monitor what’s left of the star. The star might still be there, hiding within a shell of dust expelled during the 2009 eruption. If that’s the case, it should become visible again in the coming years as the cloak dissipates.

A billion stars, new information

This video, recorded in French Guiana, says about itself:

19 December 2013

Watch a replay of ESA’s billion-star surveyor Gaia lift off.

Today, the European Space Agency is presenting the first results of their Gaia satellite mission:

“From more than a billion stars we will finally get the exact position, brightness and distance from the earth“, says [Dutch astronomer] Nelemans.

Anna Frebel digs a young universe. Stellar archaeologist has turned up stars from the second generation ever to form. By Christopher Crockett, 11:05am, September 21, 2016: here.

Freddie Mercury gets asteroid named after him

This video says about itself:

Brian May announces Asteroid 17473 Freddiemercury 04/09/2016

This video announcement was first shown at the Freddie Mercury 70th Birthday Party in Montreux, Switzerland, Sunday 4 September 2016.

In announcing Asteroid 17473 Freddie Mercury, Brian May said:

“I’m happy to be able to announce that the International Astronomical Union‘s Minor Planet Center has today designated Asteroid 17473, discovered 1991, in Freddie’s name, timed to honour his 70th birthday. Henceforth this object will be known as Asteroid 17473 Freddiemercury. Published in the September 4th announcements of the Minor Planet Center, operating out of the Smithsonian Astrophysical Observatory, this announcement is to recognise Freddie’s outstanding influence in the world.

From Science News:

Rock star Freddie Mercury now has his own space rock

The late musician is the most recent celebrity to have an asteroid named after him

By Christopher Crockett

5:49pm, September 9, 2016

Freddie Mercury, the late lead singer for the band Queen, once sang: “I’m a shooting star leaping through the sky.” Turning lyrics into reality, the rock legend now has a hunk of space rock named after him. The International Astronomical Union has renamed asteroid 1991 FM3 as (17473) Freddiemercury. Bandmate Brian May, who has a Ph.D. in astrophysics and his own eponymous asteroid, announced the change online September 4, one day before what would have been Mercury’s 70th birthday. The asteroid was discovered in 1991, the same year that Mercury died.

The asteroid named after Mercury (no relation to the planet) sits in the asteroid belt between Mars and Jupiter, and the 3.4-kilometer-wide rock loops around the sun once every 3.69 years. Mercury joins a long list of celebrity musicians to be immortalized with a small piece of the solar system, including Louie Armstrong, Frank Sinatra, David Bowie and all of the Beatles (John, Paul, George and Ringo).

Moon rocks, asteroid impacts miscalculation?

This video says about itself:

Astronomy – Ch. 8: Origin of the Solar System (16 of 19) Late Heavy Bombardment

21 March 2015

In this video I will explain how astronomers deduced that early Solar System was a very violent place.

The video shows most scientists’ views of a year ago.

However, now …

From Science News:

Moon rocks may have misled asteroid bombardment dating

Spike in impacts 3.9 billion years ago may be mathematical mirage, study finds

By Laurel Hamers

3:00pm, September 12, 2016

A barrage of rocks hitting the solar system 3.9 billion years ago could have dramatically reshaped Earth’s geology and atmosphere. But some of the evidence for this proposed bombardment might be shakier than previously believed, new research suggests. Simplifications made when dating moon rocks could make it appear that asteroid and comet impacts spiked around this time even if the collision rate was actually decreasing, scientists report the week of September 12 in the Proceedings of the National Academies of Sciences.

Many scientists think that a period of relative calm after Earth formed 4.6 billion years ago was interrupted by a period called the Late Heavy Bombardment, when rocky debris pummeled Earth and the other planets. The moon’s cratered surface holds the best evidence for this event; scientists have measured radioactive decay of argon gas trapped inside moon rocks to date when craters on the moon were formed.

Many of the hundreds of moon rocks analyzed appear to be around 3.9 billion years old. That suggests the number of rocks hitting the moon suddenly spiked at that time — evidence for a Late Heavy Bombardment.

Geochemists Patrick Boehnke and Mark Harrison of UCLA took a second look at the data. Measuring argon from the same rock at different temperatures leeches the gas from different parts of the rock’s crystals; if all those age values align, researchers can be relatively confident they’re getting an accurate age. But many of the lunar samples previously analyzed gave different ages depending on the temperature at which their argon content was measured.

Instead of colliding sharply once and sitting undisrupted, which might give more uniform age data at different temperatures, these lunar rocks were probably tossed around and slammed into other rocks many times, Boehnke says. So assigning one impact age to those rocks might be an oversimplification.

Boehnke and Harrison created a model to simulate how this simplification might affect the patterns seen when scientists looked at the ages of many rocks. The team modeled 1,000 rocks and assigned each one an impact age. Some rocks hadn’t been knocked around and had a clear impact age. Others had been smashed repeatedly, which changed their argon content and obscured the actual impact age assigned by the model.

The model assumed that asteroid collisions decreased over time — that more of the rocks were older and fewer were newer. But still, collision ages appeared to spike 3.9 billion years ago thanks to the fuzziness introduced by the disrupted rocks. So the apparent asteroid increase at that time might just be a quirk due to the way the argon dating data were compiled and analyzed, not an indication of something dramatic actually happening.

“We can’t say the Late Heavy Bombardment didn’t happen,” Boehnke says. Nor do the results invalidate the technique of argon dating, which is used widely by geologists. Instead, Boehnke says, it points to the need for more nuanced interpretation of lunar rock data.

“A lot of data that shows this complexity is being interpreted in a very simplistic way,” he says.

Planetary scientist Simone Marchi says he finds the paper “certainly convincing in saying that we have to be very careful” when interpreting argon dating data from lunar samples.

But there’s other evidence for a Late Heavy Bombardment that doesn’t rely on argon dating, such as dating from more stable radioactive elements and analysis of overlapping craters on the moon, says Marchi, of the Southwest Research Institute in Boulder, Colo. He supports the idea of a gentler Late Heavy Bombardment 4.1 billion years ago, instead of a dramatic burst 3.9 billion years ago (SN: 8/23/14, p.13).

Other recent work has also pointed out limitations in argon dating, says Noah Petro, a planetary geologist at NASA Goddard Space Flight Center in Greenbelt, Md., who wasn’t part of the study.   Collecting new samples and analyzing old ones with newer techniques could help scientists update their view of the early solar system. “We’re at this point with the moon right now where we’re finding the limitations of what we think we know.”

Where the young hot Earth cached its gold. New view offers alternative history of how precious metals sank into the planet’s core: here.

OSIRIS-REx spacecraft to asteroid 101955 Bennu today

This video from the USA says about itself:

OSIRIS-REx Tech – Surveying an Asteroid with Light

25 July 2016

NASA‘s OSIRIS-REx spacecraft is on a mission explore to near-Earth asteroid Bennu, a carbon-rich body that may contain clues to the origins of life. OSIRIS-REx is equipped with a suite of technologies designed to map and study Bennu in unprecedented detail. The OSIRIS-REx Visible and Infrared Spectrometer, or OVIRS, will look at the asteroid’s spectral signature to detect organics and other minerals. After OSIRIS-REx has thoroughly surveyed Bennu from orbit, will descend to the surface and collect a sample of the asteroid for return to Earth in 2023. In this video, OVIRS instrument scientists Dennis Reuter and Amy Simon discuss the challenges and rewards of sending a spectrometer into deep space.

Credit: NASA’s Goddard Space Flight Center/Dan Gallagher

From Science News in the USA:

OSIRIS-REx spacecraft launches tonight for mission to grab asteroid sample

by Christopher Crockett

6:00am, September 8, 2016

A spacecraft destined to bring samples of an asteroid back to Earth is scheduled to launch tonight. NASA’s OSIRIS-REx mission will launch September 8 at 7:05 p.m. EDT atop an Atlas V rocket from Cape Canaveral Air Force station in Florida. The probe will head for 101955 Bennu, a roughly 500-meter-wide asteroid whose 1.2-year orbit intersects that of Earth. Once the spacecraft arrives in late 2018, it will spend more than a year mapping the asteroid before reaching out and grabbing a sample in July 2020.

By bringing an asteroid sample to Earth, planetary scientists hope to learn more about the early solar system, what resources are available for future space explorers and how to knock off course any asteroids that pose a risk to Earth. Bennu itself has about a 1 in 2,700 chance of striking Earth late in the 22nd century.

To get a piece of Bennu, OSIRIS-REx will descend toward the surface and extend a robotic arm that will contact the surface for about 5 seconds. A puff of nitrogen gas will stir up rocks and soil, some of which will be collected in a container. The sample will be placed in a capsule for the ride home.

OSIRIS-REx will leave Bennu no earlier than March 2021. As it passes Earth in September 2023, the spacecraft will jettison its cargo, dropping the capsule in the Utah desert.