Current Events in Astronomy

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Always smart to check the expiration date on bottled water before you buy.

Earth's water older than the sun, came from interstellar ice

The water in our solar system -- including up to half of Earth's supply -- has actually been here since before the birth of the sun, according to new research.
by Michelle Starr

Somewhere between 30 and 50 percent of the water in the solar system -- including the water on Earth as well as the ice in comets, the discs around Saturn, meteorites and other planets -- was around before the birth of the sun, according to research conducted by astronomers at the University of Michigan.

In a paper published in the journal Science, the team explains that the water originated in the molecular cloud -- the nebula -- that gave birth to the sun, and predates the solar system by around a million years.

In the way of stars, the sun was born from a nebula, a cloud of dust and gas floating in space. As the nebula increased in density, its gravity would have caused it to collapse in on itself, forming a rotating ball of gas. As this ball cools, it becomes denser and its spin increases, and the gas and matter of the nebula around it form a flattened disc of material that swirls into the star's gravitational pull.

This disc is called the accretion disc -- or the protoplanetary disc. As the gas in the centre of the disc stabilises into a fully grown star, so too does the disc stabilise and coalesce into discrete planets and asteroids. A delicate balance of gravitational force (the sun's gravity attracting objects towards the sun) and centripetal force (the resisting force or the planet's spin around the sun -- think of spinning a ball on a rope) hold these objects in the solar system's orbit.

What the researchers sought to discover was whether the water was already extant in the sun's parental nebula, or whether the birth of the solar system also birthed the water within it.

"Why this is important? If water in the early Solar System was primarily inherited as ice from interstellar space, then it is likely that similar ices, along with the prebiotic organic matter that they contain, are abundant in most or all protoplanetary disks around forming stars," said Carnegie Institution for Science's Conel Alexander, who contributed to the research.

"But if the early Solar System's water was largely the result of local chemical processing during the Sun's birth, then it is possible that the abundance of water varies considerably in forming planetary systems, which would obviously have implications for the potential for the emergence of life elsewhere.
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To figure out where the water originated, the research team simulated the chemistry of the forming solar systemw
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This only says that the comets and asteroids formed soon after the supernovas that created the intersteller medium from which our solar system would form. The greater density of the supernovas ejecta make it more likely to gather the material than molecular aggregation in the solar disc which would be warmer and more energetic.

[calikid]

What's next for the European Space Agency? Glad you asked!

From ice to fire: after hopping on a comet, ESA now looks at Mercury
By Jacopo Prisco

After landing a probe on an icy comet and possibly shedding new light on the origins of life on Earth, the European Space Agency (ESA) is now looking at scorching-hot Mercury for its next mission.

The innermost planet of our solar system orbits so close to the Sun that, in some instances, surface temperature surpasses 400 °C. Areas of the planet without sunlight, on the other hand, can become as cold as -170 °C.

No other planet has variations in temperature so severe.

The reason for this is the absence of any significant atmosphere, which Mercury is too hot and too small to retain. With a diameter of just over 3,000 miles, it's just a third larger than the Moon, and smaller than two other moons in the solar system -- Saturn's Titan and Jupiter's Ganymede.

ESA's mission to Mercury will tentatively launch on 21 July 2016, to reach Mercury's orbit seven and a half years later, in 2024. The spacecraft is called BepiColombo -- in honor of Italian space pioneer Giuseppe "Bepi" Colombo.

Mercury is the least studied of the inner planets, but it has many peculiarities.

"Mercury is special," said Johannes Benkhoff, the project scientist in charge of the BepiColombo mission, "It's the densest planet in our solar system, even denser than Earth - if we consider uncompressed density - and has a magnetic field, like Earth, that no one expected before, so I guess it's a cool planet to go to."

There are many challenging aspects to a mission to Mercury, most prominently its proximity to the Sun, with its mighty gravitational pull and intense radiation.

The planet's high orbital velocity of 48 kilometers per second -- compared to Earth's 30 kilometers per second -- is also an issue. Any probe en route to Mercury must not only cover an average linear distance of 48 million miles, but carefully gauge its velocity so that it can catch the fast planet's orbit without getting sucked into the Sun's gravitational well.

As a result, only two missions have visited Mercury so far.

The first was NASA's Mariner 10, launched in 1973. Story Continues

[majicbar]

What's next for the European Space Agency? Glad you asked!

From ice to fire: after hopping on a comet, ESA now looks at Mercury
By Jacopo Prisco

After landing a probe on an icy comet and possibly shedding new light on the origins of life on Earth, the European Space Agency (ESA) is now looking at scorching-hot Mercury for its next mission.

The innermost planet of our solar system orbits so close to the Sun that, in some instances, surface temperature surpasses 400 °C. Areas of the planet without sunlight, on the other hand, can become as cold as -170 °C.

No other planet has variations in temperature so severe.

The reason for this is the absence of any significant atmosphere, which Mercury is too hot and too small to retain. With a diameter of just over 3,000 miles, it's just a third larger than the Moon, and smaller than two other moons in the solar system -- Saturn's Titan and Jupiter's Ganymede.

ESA's mission to Mercury will tentatively launch on 21 July 2016, to reach Mercury's orbit seven and a half years later, in 2024. The spacecraft is called BepiColombo -- in honor of Italian space pioneer Giuseppe "Bepi" Colombo.

Mercury is the least studied of the inner planets, but it has many peculiarities.

"Mercury is special," said Johannes Benkhoff, the project scientist in charge of the BepiColombo mission, "It's the densest planet in our solar system, even denser than Earth - if we consider uncompressed density - and has a magnetic field, like Earth, that no one expected before, so I guess it's a cool planet to go to."

There are many challenging aspects to a mission to Mercury, most prominently its proximity to the Sun, with its mighty gravitational pull and intense radiation.

The planet's high orbital velocity of 48 kilometers per second -- compared to Earth's 30 kilometers per second -- is also an issue. Any probe en route to Mercury must not only cover an average linear distance of 48 million miles, but carefully gauge its velocity so that it can catch the fast planet's orbit without getting sucked into the Sun's gravitational well.

As a result, only two missions have visited Mercury so far.

The first was NASA's Mariner 10, launched in 1973. Story Continues

Mercury's rotation is so slow that a day is longer than it's orbital period twice over. Ideally if one land on the dark side near either pole, it could send missions to the daylight side and return. Radioactive plutonium power would be necessary to operate on the night side, experience with the Curiosity rover has proven the success of such a system. The mission profile will be an interesting engineering challenge however it is done.

[calikid]

I can't help but wonder the rate of growth on a black hole this old. Did it start out big? Or just feed over the eons and grow? The idea of a black hole forming from interstellar gas is new to me, only heard of the Supernova formation prior to this.
Scientists discover black hole 12 billion times more massive than the sun

By Susannah Cullinane

Researchers in China have spotted a supermassive black hole, which they say is 12 billion times more massive than the Sun and formed around 900 million years after the Big Bang.

The black hole is larger than any of its age previously seen, the journal Nature reports.

A black hole is a dense region of space that has collapsed in on itself in a way that means nothing can escape it, not even light.

Releasing their findings in Nature, researchers led by teams from China's Peking University and the University of Arizona said the black hole -- named SDSS J010013.02 -- was six times larger than its biggest known contemporaries.

"The existence of such black holes when the universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the co-evolution of black holes and galaxies," they said.

Nature reported that lead researcher Xue-Bing Wu of Peking University and his colleagues first sighted the black hole using a telescope in Yunnan, China, and used additional telescopes around the world to examine it.

In a media release, the University of Arizona said that the black hole powered "the brightest quasar of the early universe." NASA describes quasars as "the brilliant beacons of light that are powered by black holes feasting on captured material, and in the process, heating some of the matter to millions of degrees."

Team member Fuyun Bian, from the Australian National University, said that the light from a quasar was thought to push back material behind it and limit the growth of black holes.

"However this black hole at the center of the quasar gained enormous mass in a short period of time," Bian said.

Another researcher, Chris Willott, told Nature that a possible explanation could be that some black holes were formed by the collapse of a very large gas cloud -- rather than that of a single star.
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[CasperParks]

I can't help but wonder the rate of growth on a black hole this old. Did it start out big? Or just feed over the eons and grow? The idea of a black hole forming from interstellar gas is new to me, only heard of the Supernova formation prior to this.
Scientists discover black hole 12 billion times more massive than the sun

By Susannah Cullinane

Researchers in China have spotted a supermassive black hole, which they say is 12 billion times more massive than the Sun and formed around 900 million years after the Big Bang.

The black hole is larger than any of its age previously seen, the journal Nature reports.

A black hole is a dense region of space that has collapsed in on itself in a way that means nothing can escape it, not even light.

Releasing their findings in Nature, researchers led by teams from China's Peking University and the University of Arizona said the black hole -- named SDSS J010013.02 -- was six times larger than its biggest known contemporaries.

"The existence of such black holes when the universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the co-evolution of black holes and galaxies," they said.

Nature reported that lead researcher Xue-Bing Wu of Peking University and his colleagues first sighted the black hole using a telescope in Yunnan, China, and used additional telescopes around the world to examine it.

In a media release, the University of Arizona said that the black hole powered "the brightest quasar of the early universe." NASA describes quasars as "the brilliant beacons of light that are powered by black holes feasting on captured material, and in the process, heating some of the matter to millions of degrees."

Team member Fuyun Bian, from the Australian National University, said that the light from a quasar was thought to push back material behind it and limit the growth of black holes.

"However this black hole at the center of the quasar gained enormous mass in a short period of time," Bian said.

Another researcher, Chris Willott, told Nature that a possible explanation could be that some black holes were formed by the collapse of a very large gas cloud -- rather than that of a single star.
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Lot of great scientific theories regarding black holes. As we progress into the stars, many of those theories could be upended.

Exploration of our Environment is not strictly Earthbound and must include solar, planetary and beyond.

[calikid]

So..... 6 more weeks of winter?

Comet flyby: OSIRIS catches glimpse of Rosetta’s shadow

Images from the OSIRIS scientific imaging camera taken during the close flyby on 14 February have now been downlinked to Earth, revealing the surface of Comet 67P/C-G in unprecedented detail, and including the shadow of the spacecraft encircled in a wreath of light.

The image released today shows an area near the edge of the comet’s “belly” close to the Imhotep-Ash regional boundary, where a mesh of steep slopes separates smooth-looking terrains from a craggier area. The image was taken from a distance of 6 km from the comet’s surface and has a resolution of 11 cm/pixel. It covers an area of 228 x 228 m.

To better identify the exact region on the comet, in the graphic below we compare the new OSIRIS narrow-angle camera image with a wider view of the comet, along with the NAVCAM image taken at 14:15 UT, noting that there are uncertainties in the distance to the surface and change in perspective between the images. Indeed, while the match on the smooth-looking region at the bottom of the NAC image in the displayed orientation is good, it is harder to match the upper half because of the lack of shadows in the NAC image, and because the geometry/viewing perspective has changed between the images. This means that the NAC image would have to be distorted and "draped" over the surface to fit the NAVCAM properly. To better understand the relationship of the images, you can download a short movie that fades through the images here.

During the flyby, Rosetta not only passed closer by the comet than ever before, but also passed through a unique observational geometry: for a short time the Sun, spacecraft, and comet were exactly aligned. In this geometry, surface structures cast almost no shadows, and therefore the reflection properties of the surface material can be discerned.

“Images taken from this viewpoint are of high scientific value,” says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. “This kind of view is key for the study of grain sizes.”

As a side effect of this exceptional observational geometry, Rosetta’s shadow can be seen cast on the surface of Comet 67P/C-G as a fuzzy rectangular-shaped dark spot surrounded by a bright halo-like region.

The shadow is fuzzy and somewhat larger than Rosetta itself, measuring....
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To bad Venus has runaway greenhouse gases. Might have been more habitable than Mars. If only....
Naked Venus: What it looks like under its cloud clothes

Take a peek beneath the carbon-dioxide clouds of Venus with radar data that sees its surface secrets.

by Amanda Kooser

Venus is a shy planet that hangs out in the solar system, 25 million miles away from Earth. When seen from a ground telescope here, it looks like a clouded marble. The surface is hidden away under a thick coating of carbon-dioxide clouds.

It turns out Venus is hiding some dramatic surface features ranging from volcanoes to craters. A new image released by the National Radio Astronomy Observatory (NRAO) lifts the veil for a look at what lies beneath the clouds.

The image came about by combining the work of the National Science Foundation's Green Bank Telescope (a radio telescope in West Virginia) and the radar transmitter at the Arecibo Observatory in Puerto Rico.

The NRAO explains how it works: "The radar signals from Arecibo passed through both our planet's atmosphere and the atmosphere of Venus, where they hit the surface and bounced back to be received by the GBT in a process known as bistatic radar."

The result is an image showing mountains and craters.
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The picture of Venus was combined with radar information collected in 2012.
NRAO/AUI/NSF, Arecibo

[calikid]

Fires the imagination, can some primitive lifeform possibly exist in that cold dark ocean?

Jupiter's Moon Ganymede Has a Salty Ocean with More Water than Earth
By Miriam Kramer

A salty ocean is lurking beneath the surface of Jupiter's largest moon, Ganymede, scientists using the Hubble Space Telescope have found.

The ocean on Ganymede — which is buried under a thick crust of ice — could actually harbor more water than all of Earth's surface water combined, according to NASA officials. Scientists think the ocean is about 60 miles (100 kilometers) thick, 10 times the depth of Earth's oceans, NASA added. The new Hubble Space Telescope finding could also help scientists learn more about the plethora of potentially watery worlds that exist in the solar system and beyond.

"The solar system is now looking like a pretty soggy place," Jim Green, NASA's director of planetary science, said during a news teleconference...
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[CasperParks]

Fires the imagination, can some primitive lifeform possibly exist in that cold dark ocean?

Jupiter's Moon Ganymede Has a Salty Ocean with More Water than Earth
By Miriam Kramer

A salty ocean is lurking beneath the surface of Jupiter's largest moon, Ganymede, scientists using the Hubble Space Telescope have found.

The ocean on Ganymede — which is buried under a thick crust of ice — could actually harbor more water than all of Earth's surface water combined, according to NASA officials. Scientists think the ocean is about 60 miles (100 kilometers) thick, 10 times the depth of Earth's oceans, NASA added. The new Hubble Space Telescope finding could also help scientists learn more about the plethora of potentially watery worlds that exist in the solar system and beyond.

"The solar system is now looking like a pretty soggy place," Jim Green, NASA's director of planetary science, said during a news teleconference...
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New life forms are discovered in Earth's oceans at greater and greater depths, plus at both poles. It is highly possible oceans under layers of ice and or land have life on other planets.

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Haste makes waste.

Big Bang breakthrough team allows they may be wrong

American astrophysicists who announced just months ago what they deemed a breakthrough in confirming how the universe was born now admit they may have got it wrong.

The team said it had identified gravitational waves that apparently rippled through space right after the Big Bang.

If proven to be correctly identified, these waves -- predicted in Albert Einstein's theory of relativity -- would confirm the rapid and violent growth spurt of the universe in the first fraction of a second marking its existence, 13.8 billion years ago.

The apparent first direct evidence of such so-called cosmic inflation -- a theory that the universe expanded by 100 trillion trillion times in barely the blink of an eye -- was announced in March by experts at the Harvard-Smithsonian Center for Astrophysics.

The detection was made with the help of a telescope called BICEP2, stationed at the South Pole.

After weeks in which they avoided the media, the team published its work Thursday in the US journal Physical Review Letters.

In a summary, the team said their models "are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal," as stated by other scientists who questioned their conclusion. Story COntinues

In a discussion posted in space.com another experiment better positioned has confirmed the general idea of the inflationary growth of the Universe, see:

http://m.space.com/28808-did-cosmic-...pr=17610706465