Posts Tagged ‘Nasa’

Wise telescope data
Wise has been able to see objects not visible to past science instruments

A space telescope has added to its list of spectacular finds, spotting millions of supermassive black holes and blisteringly hot, “extreme” galaxies.

The finds, by US space agency Nasa’s Wide-Field Infrared Survey Explorer (Wise), once lay obscured behind dust.

But Wise can see in wavelengths correlated with heat, seeing for the first time some of the brightest objects in the Universe.

The haul will help astronomers work out how galaxies and black holes form.

It is known that most large galaxies host black holes at their centres, sometimes feeding on nearby gas, dust and stars and sometimes spraying out enough energy to halt star formation altogether.

How the two evolve together has remained a mystery, and the Wise data are already yielding some surprises.

Wise gives astronomers what is currently a unique view on the cosmos, looking at wavelengths of light far beyond those we can see but giving information that we cannot get from wavelengths we can.

Continue reading the main story

Black holes

Artist's depiction of black hole
  • These are regions of space where gravity is so powerful that not even light can escape
  • One way they can form is when huge stars collapse in on themselves
  • So-called supermassive black holes sit at the centres of galaxies, including the Milky Way

Among its other discoveries, in 2011 Wise spotted in a “Trojan” asteroid ahead of the Earth in its orbit.

But with the latest results, Wise has come into its own as an unparalleled black hole hunter.

“We’ve got the black holes cornered,” said Daniel Stern of Nasa’s Jet Propulsion Laboratory (JPL), lead author of one of the three studies presented on Wednesday.

Dr Stern and his colleagues used the Nuclear Spectroscopic Telescope Array (Nustar) space telescope to examine the X-rays coming out of the black hole candidates spotted by Wise, presenting their findings in a paper to appear in Astrophysical Journal.

“Wise is finding them across the full sky, while Nustar is giving us an entirely new look at their high-energy X-ray light and learning what makes them tick,” he said.

The other two studies presented – one already published in Astrophysical journal and another yet to appear – focussed on extremely hot, bright galaxies that have until now remained hidden: hot dust-obscured galaxies, or hot-Dogs.

There are so far about 1,000 candidate galaxies, some of which can out-shine our Sun by a factor of 100 trillion.

“These dusty, cataclysmically forming galaxies are so rare Wise had to scan the entire sky to find them,” said Peter Eisenhardt of JPL, lead author of the paper describing Wise’s first hot-Dog find.

“We are also seeing evidence that these record-setters may have formed their black holes before the bulk of their stars. The ‘eggs’ may have come before the ‘chickens’.”

The data from the Wise mission are made publicly available so that scientists outside the collaboration can also carry out their own studies, so the future will hold a wealth of studies from these extreme and otherwise hidden corners of the Universe.

Nasa sky probe sends back images
Trojan rock seen in Earth’s orbit
Huge cloud heading for black hole

A space telescope has added to its list of spectacular finds, spotting millions of supermassive black holes and blisteringly hot, “extreme” galaxies.

The finds, by US space agency Nasa’s Wide-Field Infrared Survey Explorer (Wise), once lay obscured behind dust.

But Wise can see in wavelengths correlated with heat, seeing for the first time some of the brightest objects in the Universe.

The haul will help astronomers work out how galaxies and black holes form.

It is known that most large galaxies host black holes at their centres, sometimes feeding on nearby gas, dust and stars and sometimes spraying out enough energy to halt star formation altogether.

How the two evolve together has remained a mystery, and the Wise data are already yielding some surprises.

Wise gives astronomers what is currently a unique view on the cosmos, looking at wavelengths of light far beyond those we can see but giving information that we cannot get from wavelengths we can.
Continue reading the main story
Black holes
Artist’s depiction of black hole

These are regions of space where gravity is so powerful that not even light can escape
One way they can form is when huge stars collapse in on themselves
So-called supermassive black holes sit at the centres of galaxies, including the Milky Way

Brian Cox on what happens near black holes

Among its other discoveries, in 2011 Wise spotted in a “Trojan” asteroid ahead of the Earth in its orbit.

But with the latest results, Wise has come into its own as an unparalleled black hole hunter.

“We’ve got the black holes cornered,” said Daniel Stern of Nasa’s Jet Propulsion Laboratory (JPL), lead author of one of the three studies presented on Wednesday.

Dr Stern and his colleagues used the Nuclear Spectroscopic Telescope Array (Nustar) space telescope to examine the X-rays coming out of the black hole candidates spotted by Wise, presenting their findings in a paper to appear in Astrophysical Journal.

“Wise is finding them across the full sky, while Nustar is giving us an entirely new look at their high-energy X-ray light and learning what makes them tick,” he said.

The other two studies presented – one already published in Astrophysical journal and another yet to appear – focussed on extremely hot, bright galaxies that have until now remained hidden: hot dust-obscured galaxies, or hot-Dogs.

There are so far about 1,000 candidate galaxies, some of which can out-shine our Sun by a factor of 100 trillion.

“These dusty, cataclysmically forming galaxies are so rare Wise had to scan the entire sky to find them,” said Peter Eisenhardt of JPL, lead author of the paper describing Wise’s first hot-Dog find.

“We are also seeing evidence that these record-setters may have formed their black holes before the bulk of their stars. The ‘eggs’ may have come before the ‘chickens’.”

The data from the Wise mission are made publicly available so that scientists outside the collaboration can also carry out their own studies, so the future will hold a wealth of studies from these extreme and otherwise hidden corners of the Universe.

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Artist's conception of Kepler 22-b

Painting of Milky Way galaxy used as backgroun...

Image via Wikipedia

The planet, shown here in an artist’s conception, circles its host star in 290 days

Astronomers have confirmed the existence of an Earth-like planet in the “habitable zone” around a star not unlike our own.

The planet, Kepler 22-b, lies about 600 light-years away and is about 2.4 times the size of Earth, and has a temperature of about 22C.

It is the closest confirmed planet yet to one like ours – an “Earth 2.0”.

However, the team does not yet know if Kepler 22-b is made mostly of rock, gas or liquid.

During the conference at which the result was announced, the Kepler team also said that it had spotted some 1,094 new candidate planets – nearly doubling the telescope’s haul of potential far-flung worlds.

Kepler 22-b was one of 54 exoplanet candidates in habitable zones reported by the Kepler team in February, and is just the first to be formally confirmed using other telescopes.

More of these “Earth 2.0” candidates are likely to be confirmed in the near future, though a redefinition of the habitable zone’s boundaries has brought that number down to 48. Ten of those are Earth-sized.

‘Superb opportunity’

The Kepler space telescope was designed to look at a fixed swathe of the night sky, staring intently at about 150,000 stars. The telescope is sensitive enough to see when a planet passes in front of its host star, dimming the star’s light by a minuscule amount.

Kepler identifies these slight changes in starlight as candidate planets, which are then confirmed by further observations by Kepler and other telescopes in orbit and on Earth.


Kepler Space Telescope

Infographic (BBC)
  • Stares fixedly at a patch corresponding to 1/400th of the sky
  • Looks at more than 155,000 stars
  • Has so far found 2,326 candidate planets
  • Among them are 207 Earth-sized planets, 10 of which are in the “habitable zone” where liquid water can exist

Kepler 22-b lies 15% closer to its sun than the Earth is to our Sun, and its year takes about 290 days. However, the planet’s host star puts out about 25% less light, keeping the planet at its balmy temperature that would support the existence of liquid water.

The Kepler team had to wait for three passes of the planet before upping its status from “candidate” to “confirmed”.

“Fortune smiled upon us with the detection of this planet,” said William Borucki, Kepler principal investigator at Nasa’s Ames Research Center.

“The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season.”

The results were announced at the Kepler telescope’s first science conference, alongside the staggering number of new candidate planets. The total number of candidates spotted by the telescope is now 2,326 – of which 207 are approximately Earth-sized.

In total, the results suggest that planets ranging from Earth-sized to about four times Earth’s size – so-called “super-Earths” – may be more common than previously thought.

As candidates for planets similar to Earth are confirmed, the Search for Extraterrestrial Intelligence (Seti) has a narrower focus for its ongoing hunt.

“This is a superb opportunity for Seti observations,” said Jill Tarter, the director of the Center for Seti Research at the Seti Institute.

“For the first time, we can point our telescopes at stars, and know that those stars actually host planetary systems – including at least one that begins to approximate an Earth analogue in the habitable zone around its host star.

Kepler 22-b infographic