Category: European Space Agency

Supermassive black hole spins at nearly the speed of light

On By A.P.In black hole, Einstein, European Space Agency, NASA, Nature, NGC 1365 galaxy, Nuclear Spectroscopic Telescope Array, NuSTAR space telescope, Science, Space and Time, speed of light, XMM-Newton satelliteLeave a comment

blackhole
This artist’s concept illustrates a supermassive black hole with millions to billions times the mass of our sun. It’s surrounded by matter flowing onto the black hole in what is termed an accretion disk. Also shown is an outflowing jet of energetic particles, believed to be powered by the black hole’s spin. High energy X-radiation lights up the disk, which reflects it, making the disk a source of X-rays. The reflected light enables astronomers to see how fast matter is swirling in the inner region of the disk, and ultimately to measure the black hole’s spin rate.

Nothing can escape a black hole, even light, because to wrench away from its titanic gravitational pull, you’d have to move faster than light is capable of traveling. And nothing can do that, as far as anyone knows. As matter falls into a black hole’s gaping maw, it superheats to millions of degrees, screaming a final cry of X-rays as it is torn apart. At a specific point called an event horizon, the matter disappears and is never heard from again.

A pair of X-ray telescopes recently watched some of these X-ray death gasps and were able to figure out how fast a black hole is spinning. This is “hugely important” for black hole science, according to researchers working with NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR space telescope. One particularly cool finding: The black hole is spinning almost as fast as Einstein’s theory of gravity says it possibly could. It’s spinning at almost the speed of light.

The galaxy in question is called NGC 1365, which is about twice the size of the Milky Way and located about 60 million light years away. The black hole is about 2 million times more massive than the sun. Scientists using NuSTAR and the European Space Agency’s XMM-Newton satellite wanted to measure how fast it is spinning. This is a key feature of black holes that is related to their size and the way they gobble up stars, gas and even other black holes.

The problem is that black holes are hard to study, because, you know, not even light can escape them. To measure them, you have to measure their effect on their surroundings–like the X-rays emitted by dying matter. This is hard to do because objects between us and them can get in the way, however, making the X-rays look distorted. There have been two competing models explaining why the X-rays look warped: Either gravitational distortion caused by black hole gravity, or distortion caused by intervening clouds of gas and dust.

In this new study, NuSTAR and XMM-Newton set out to determine which one is right. The telescopes carefully traced the X-rays emitted at the very, very edge of the black hole, right near the event horizon, or the point of no return. By combining their distinct viewing abilities, the two telescopes were able to see a wide range of X-ray energies, and figure out that the X-rays are not actually distorted by intervening gas clouds. They look distorted because the black hole is spinning, and its immense gravity warps spacetime as it swirls around. This information was used to tell just how fast the black hole is spinning: Just below the universal speed limit.

Along with new information about this particular black hole, this study suggests that black hole observations can remove a little bit of ambiguity. This will help astronomers continue to unravel the mysteries of these galactic monsters. A paper describing the findings is published last week in Nature.

http://www.popsci.com/science/article/2013-02/new-telescope-discovery-distant-gargantuan-black-hole-spins-near-light-speed

Ozone Hole Shrinks to Record Low

On By A.P.In Antarctica, CFCs, chlorofluorocarbons, Climate Change, environment, ESA, European Space Agency, Global Warming, ozone, ozone holeLeave a comment

South_Pole_ozone-130212

Good news from Antarctica: The hole in the ozone layer is shrinking, new measurements reveal.

Ozone is a molecule made of three oxygen atoms. It’s relatively highly concentrated in a particular layer of the stratosphere about 12 miles to 19 miles (20 to 30 kilometers) above Earth’s surface. This ozone layer prevents ultraviolet light from reaching Earth’s surface — a good thing, given that UV light causes sunburn and skin cancer.

Ever since the early 1980s, though, a hole in this layer has developed over Antarctica during September to November, decreasing ozone concentration by as much as 70 percent. The cause is human-produced chlorofluorocarbons (CFCs), which were once heavily used in aerosols and refrigeration.

By international agreement, CFCs have been phased out of use. The policy has real effects, new satellite observations reveal. In 2012, the hole in the ozone layer over Antarctica was smaller than it has ever been in the last 10 years.

The new observations, announced by the European Space Agency (ESA) on Feb. 8, come from Europe’s Met Op weather satellite, which has an instrument specifically designed to sense ozone concentrations. The findings suggest that the phase-out of CFCs is working, the ESA reports.

Antarctica is particularly vulnerable to ozone-depleting substances, because high winds cause a vortex of cold air to circulate over the continent. In the resulting frigid temperatures, CFCs are especially effective at depleting ozone. The result is that people in the Southern Hemisphere are at increased risk of exposure from UV radiation.

CFCs persist in the atmosphere for a long time, so it may take until the middle of the century for ozone concentrations to rebound to 1960s levels, the ESA reports. However, the hole in the ozone over Antarctica should completely close in the next few decades.

http://www.livescience.com/27049-ozone-hole-shrinks-record-low.html

British company claims biggest engine advance since the jet: the SABRE engine

On By A.P.In Britain, engine, Engineering, ESA, European Space Agency, Helical Bar, Inventions, Kebmodee, Mark Ford, Nigel McNair Scott, propulsion engineering, Reaction Engines Ltd, Richard Varvill, Rolls-Royce, SABRE, SABRE engine, Science, Skylon, Space and Time, space plane, Technology, Tim HayterLeave a comment

A Skylon in flight with a cutaway of the SABRE engine

 

A small British company with a dream of building a re-usable space plane has won an important endorsement from the European Space Agency (ESA) after completing key tests on its novel engine technology.

Reaction Engines Ltd believes its Sabre engine, which would operate like a jet engine in the atmosphere and a rocket in space, could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away.

That ambition was given a boost on Wednesday by ESA, which has acted as an independent auditor on the Sabre test programme.

“ESA are satisfied that the tests demonstrate the technology required for the Sabre engine development,” the agency’s head of propulsion engineering Mark Ford told a news conference.

“One of the major obstacles to a re-usable vehicle has been removed,” he said. “The gateway is now open to move beyond the jet age.”

The space plane, dubbed Skylon, only exists on paper. What the company has right now is a remarkable heat exchanger that is able to cool air sucked into the engine at high speed from 1,000 degrees Celsius to minus 150 degrees in one hundredth of a second.

This core piece of technology solves one of the constraints that limit jet engines to a top speed of about 2.5 times the speed of sound, which Reaction Engines believes it could double.

With the Sabre engine in jet mode, the air has to be compressed before being injected into the engine’s combustion chambers. Without pre-cooling, the heat generated by compression would make the air hot enough to melt the engine.

The challenge for the engineers was to find a way to cool the air quickly without frost forming on the heat exchanger, which would clog it up and stop it working.

Using a nest of fine pipes that resemble a large wire coil, the engineers have managed to get round this fatal problem that would normally follow from such rapid cooling of the moisture in atmospheric air.

They are tight-lipped on exactly how they managed to do it.

“We are not going to tell you how this works,” said the company’s chief designer Richard Varvill, who started his career at the military engine division of Rolls-Royce. “It is our most closely guarded secret.”

The company has deliberately avoided filing patents on its heat exchanger technology to avoid details of how it works – particularly the method for preventing the build-up of frost – becoming public.

The Sabre engine could take a plane to five times the speed of sound and an altitude of 25 km, about 20 percent of the speed and altitude needed to reach orbit. For space access, the engines would then switch to rocket mode to do the remaining 80 percent.

Reaction Engines believes Sabre is the only engine of its kind in development and the company now needs to raise about 250 million pounds ($400 million) to fund the next three-year development phase in which it plans to build a small-scale version of the complete engine.

Chief executive Tim Hayter believes the company could have an operational engine ready for sale within 10 years if it can raise the development funding.

The company reckons the engine technology could win a healthy chunk of four key markets together worth $112 billion (69 billion pounds) a year, including space access, hypersonic air travel, and modified jet engines that use the heat exchanger to save fuel.

The fourth market is unrelated to aerospace. Reaction Engines believes the technology could also be used to raise the efficiency of so-called multistage flash desalination plants by 15 percent. These plants, largely in the Middle East, use heat exchangers to distil water by flash heating sea water into steam in multiple stages.

The firm has so far received 90 percent of its funding from private sources, mainly rich individuals including chairman Nigel McNair Scott, the former mining industry executive who also chairs property developer Helical Bar.

Chief executive Tim Hayter told Reuters he would welcome government investment in the company, mainly because of the credibility that would add to the project.

But the focus will be on raising the majority of the 250 million pounds it needs now from a mix of institutional investors, high net worth individuals and possibly potential partners in the aerospace industry.

Sabre produces thrust by burning hydrogen and oxygen, but inside the atmosphere it would take that oxygen from the air, reducing the amount it would have to carry in fuel tanks for rocket mode, cutting weight and allowing Skylon to go into orbit in one stage.

Scramjets on test vehicles like the U.S. Air Force Waverider also use atmospheric air to create thrust but they have to be accelerated to their operating speed by normal jet engines or rockets before they kick in. The Sabre engine can operate from a standing start.

If the developers are successful, Sabre would be the first engine in history to send a vehicle into space without using disposable, multi-stage rockets.

Skylon is years away, but in the meantime the technology is attracting interest from the global aerospace industry and governments because it effectively doubles the technical limits of current jet engines and could cut the cost of space access.

The heat exchanger technology could also be incorporated into a new jet engine design that could cut 5 to 10 percent – or $10 (6.25 pounds)-20 billion – off airline fuel bills.

That would be significant in an industry where incremental efficiency gains of one percent or so, from improvements in wing design for instance, are big news.

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

http://uk.reuters.com/article/2012/11/28/uk-science-spaceplane-idUKBRE8AR0R520121128