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Astronomers have spotted Mingus, the most distant supernova ever seen.
Mingus was described at the 221st American Astronomical Society meeting in the US.
These lightshows of dying stars have been seen since ancient times, but modern astronomers use details of their light to probe the Universe’s secrets.
Ten billion light-years distant, Mingus will help shed light on so-called dark energy, the force that appears to be speeding up cosmic expansion.
Formally called SN SCP-0401, the supernova was something of a chance find in a survey carried out in part by the Supernova Cosmology Project (SCP) using the Hubble space telescope, first undertaken in 2004.
But the data were simply not good enough to pin down what was seen. As David Rubin of the University of California, Berkeley, lead author on the study, told the AAS meeting, “for a sense of brightness, this supernova is about as bright as a firefly viewed from 3,000 miles away”.
Further news had to wait until astronauts installed the Wide Field Camera 3 on the Hubble telescope in 2009 and again trained it on the candidate, which had – in an SCP tradition of naming supernovae after composers – already been named after jazz musician Charles Mingus.
“Unfortunately, it took the development of Wide Field Camera 3 to bring home what the [2004] measurements meant,” said David Rubin.
“The sensitivity is a few times better, which makes a huge difference, and we have a much cleaner image.”
Astronomers have spotted Mingus, the most distant supernova ever seen
The team went on to confirm that the supernova was in fact a Type 1a – a particular class of exploded star whose light occurs in such a regular way that it is known as a “standard candle”.
What interests astronomers trying to find ever more distant Type 1a supernovae – distant both in space and in time – is the chance to compare them to better-known, more local supernovae.
“We were able to watch these changes in brightness and spectral features for an event that lasted just a few weeks almost 10 billion years ago,” said Saul Perlmutter, who leads the Supernova Cosmology Project.
Prof. Saul Perlmutter shared the 2011 Nobel prize in physics for work with Type 1a supernovae that proved our Universe is speeding up in its expansion.
Elucidating the mysterious force, “dark energy”, which has been invoked as the cause of the expansion, will require careful study of supernovae all the way back to the epoch of the earliest stars.
“We’re seeing two-thirds of the way back to the beginning of the Universe, and we’re getting a little bit of history where the physics of what makes a supernova explode have to all work out the same way there as they do near here,” he told the meeting.
The group’s study is published online and will appear in the Astrophysical Journal on January 20.
The meeting also heard from Joshua Frieman, director of the Dark Energy Survey – a five-year mission using the most powerful camera ever trained on the skies to get to the bottom of the dark matter mystery.
The phone-booth-sized Dark Energy Camera snapped its first images in September 2012 and will begin its formal mission in September this year, looking not only at supernovae but also at three other dark-energy signatures in the cosmos.
Prof. Joshua Frieman said the distant supernova result fits neatly into a story that he hoped the Dark Energy Survey would explore in great detail.
“What they’re doing is using the Hubble telescope to go really deep – we’re going to use the Dark Energy Survey to go very broad,” he explained.
“They’re finding tens of supernovae at these high [distances], and we’re going to find thousands of supernovae not quite as deep. You really need both of those together to really make progress in trying to figure out why the Universe is speeding up.”
NASA’s Dawn satellite has left the giant Asteroid Vesta after 13 months of study.
A signal from Dawn probe confirming that it had escaped the gravitational bounds of the 530 km-wide rock was received by NASA on Wednesday.
The spacecraft’s ion engine is now pushing it on to an even bigger target in the belt of asteroids between Mars and Jupiter – the dwarf planet Ceres.
Dawn is expected to reach this 950 km-wide body in early 2015.
Before departing on its long cruise to the new destination, the probe trained its camera system on Vesta’s northern pole.
The pictures reveal mountains and craters that are being seen for the very first time. Only now, as Dawn heads away, has the Sun risen high enough in the sky to illuminate the highest latitudes.
Dawn satellite has left the giant Asteroid Vesta after 13 months of study
Scientists are poring over the images to see what interpretation they can put on the terrain.
Vesta has the appearance of a punctured football – the result of two mighty impacts that removed huge volumes of rock from its southern pole.
These collisions sent shockwaves rippling across the asteroid, producing a deep system of troughs that extends around the object’s equator.
Researchers have speculated that this disturbance might also be reflected in the features hitherto obscured at the northern pole.
However, Dawn’s principal investigator Prof. Chris Russell said a definitive statement on such matters would have to wait on a detailed assessment of the new pictures.
“We haven’t got together to discuss it carefully yet,” he said.
“[The region] is not as jumbled as I had expected; it’s more subtle than I had expected – but the people who are experts in this particular area do feel that there is an effect of the southern impact.”
The Dawn mission has returned a great swathe of data to transform our understanding of Vesta.
Before the probe’s arrival in July last year, the best views of the asteroid were some fuzzy pictures acquired by the Hubble Space Telescope.
Dawn studied in detail the pattern of minerals exposed at Vesta’s surface and also mapped the diverse geological features shaping its terrain.
These observations have enabled scientists to elucidate a history for the colossal rock.
They now regard it as a unique body – the only remaining example of the original objects that came together to form the rocky planets, like Earth and Mars, some 4.6 billion years ago.
It is clear now that Vesta has a layered interior, with a metal-rich core that takes up some 18% of the body by mass.
All of the other objects like it at the Solar System’s birth were either obliterated in the intense collisional environment that existed back then or were incorporated into successively larger aggregations of material that eventually produced the planets we recognize today.
Perhaps the stand-out discovery is the definitive association that can now be made between Vesta and the howardite-eucrite-diogenite, or HED, class of meteorites that regularly fall to Earth.
From telescopic observations, researchers had always suspected these meteorites came from Vesta. But the signatures of pyroxene – a mineral rich in iron and magnesium – in those meteorites have now been matched precisely with the mineral signatures spied in Vesta’s surface by Dawn’s instruments.
It is highly likely that much of the HED material was thrown off Vesta in those two big impacts at the southern pole.
“We have used those meteorites and their chemical analysis to tell a story about the formation of the Solar System and its evolution, and if that was wrong we’d have had a lot of explaining and new work to do. The fact that it is right, and we’ve confirmed it, is really very good. It makes our lives a lot simpler,” said Prof. Chris Russell, who is affiliated to the University of California, Los Angeles.
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Hubble Space Telescope has been used to work out on when precisely our Milky Way Galaxy will crash into its neighbor, Andromeda, astronomers announce.
Milky Way and Andromeda are being pulled together by their mutual gravity and the scientists expect them to begin to merge in about four billion years’ time.
A further two billion years on and they will appear as a single entity.
Our Sun’s position will be disturbed but the star and its planets are in little danger of being destroyed.
Viewed from Earth, however, the night sky should look fairly spectacular. That is assuming, of course, that a human species is still around billions of years into the future to look upwards.
“Today, the Andromeda Galaxy appears to us on the sky as a small fuzzy object that was first seen by ancient astronomers more than one thousand years ago,” said lead researcher Roeland van der Marel from the Space Telescope Science Institute in Baltimore, US.
“Few things fascinate humans more than to know what our cosmic destiny and future fate will be. The fact that we can predict that this small fuzzy object will one day come to engulf and enshroud our Sun and Solar System is a truly remarkable and fascinating finding.”
Milky Way and Andromeda are being pulled together by their mutual gravity and the scientists expect them to begin to merge in about four billion years' time
It has long been known that the two galaxies have been heading in the general direction of each other.
They are separated by about 2.5 million light-years, but are converging at something like 400,000 km/h (250,000 mph). The new Hubble data provides fresh insight on when and how a union is likely to unfold.
This is possible because the orbiting observatory has measured in finer detail than ever before the motions of select regions of Andromeda, also frequently referred to by its catalogue name M31.
“It’s necessary to know not only how Andromeda is moving in our direction but also what its sideways motion is, because that will determine whether Andromeda will miss us at a distance or whether it might be heading straight for us,” explained Dr Roeland van der Marel.
“Astronomers have tried to measure the sideways motion for over a century. However, this was always unsuccessful because the available techniques were not sufficient to perform the measurement.
“For the very first time, we’ve been able to measure the sideways motion – in astronomy, also known as proper motion – of the Andromeda Galaxy using the unique observational capabilities of the Hubble Space Telescope.”
Computer simulations based on Hubble’s data indicate the two great masses of stars will eventually shape themselves into a single elliptical galaxy similar to the kind commonly seen in the local Universe.
However, although the galaxies will plough into each other, individual stars will not collide because the space between them will still be huge.
Nonetheless, the gravitational disturbance will shift the location of our Solar System, the researchers believe.
It is likely also that the merger will kick off a vigorous phase of new star formation as gas clouds are perturbed and collapse in on themselves.
From their observations, the scientists say it is quite possible Andromeda’s small companion, the Triangulum galaxy, or M33, will also join the fray.
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Astronomers using Hubble Space Telescope have confirmed the existence of a new class of planet: a waterworld with a thick, steamy atmosphere.
The exoplanet GJ 1214b is a so-called “Super Earth” – bigger than our planet, but smaller than gas giants such as Jupiter.
Observations using the Hubble telescope now seem to confirm that a large fraction of its mass is water.
The planet’s high temperatures suggest exotic materials might exist there.
“GJ 1214b is like no planet we know of,” said lead author Zachory Berta, from the Harvard Smithsonian Center for Astrophysics.
The planet was discovered in 2009 by ground-based telescopes. It is about 2.7 times the Earth’s diameter, but weighs almost seven times as much. It orbits its red-dwarf star at a distance of just two million km, meaning temperatures on GJ 1214b probably reach above 200C.
In 2010, astronomers released measurements of its atmosphere. These suggested that GJ 1214b’s atmosphere was probably made up of water, but there was another possibility – that the planet was covered in a haze, of the type that envelopes Saturn’s moon Titan.
Exoplanet GJ 1214b, so-called "Super Earth”, is bigger than our planet, but smaller than gas giants such as Jupiter
Zachory Berta and his colleagues used the Hubble Space Telescope’s wide-field camera to study the planet as it crossed in front of its star – a transit. During these transits, the star’s light is filtered through the planet’s atmosphere, giving clues to the mixture of gases present.
The researchers said their results are more consistent with a dense atmosphere of water vapor, than one with a haze.
Calculations of the planet’s density also suggest that GJ 1214b has more water than Earth. This means the internal structure of this world would be very different to that of our own.
“The high temperatures and pressures would form exotic materials like <<hot ice>> or <<superfluid water>>, substances that are completely alien to our everyday experience,” said Dr. Zachory Berta.
The planet’s short distance from Earth makes it a likely candidate for follow-up observations with the James Webb Space Telescope, which may launch by the end of this decade.
The study has been accepted for publication by the Astrophysical Journal.
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An image of a “barred spiral” galaxy that could help us better understand our own Milky Way has been captured by Hubble space telescope.
Most of the known spiral galaxies fall into this “barred” category – which are defined by the pronounced bar structure across their centres.
The presence of this structure may be an indication of a galaxy’s age.
Two-thirds of nearby, younger galaxies have the bar, while only a fifth of older, more distant spirals have it.
An image of a "barred spiral" galaxy that could help us better understand our own Milky Way has been captured by Hubble space telescope
The new picture also continues the Hubble space telescope’s long heritage of striking astronomical images.
In the upper left of the image is a cluster showing recent star formation that is just visible to Hubble’s cameras.
But it is a bright source in X-ray light; astronomers believe that this IXO-5 X-ray source is actually a “binary” system comprising a star and a black hole in mutual orbit.
