Observing Archives

April 2, 2008December 24, 2015 by Ian O'Neill

A Black Hole Observed in the Heart of Mysterious Omega Centauri

Omega Centauri is a strange thing. It’s been classified as a star, then a nebula, then a globular cluster and now it’s thought to be a dwarf galaxy missing its outer stars. Why is it in such a mess? How can this oddball galaxy be explained? New research suggests it has an intermediate-black hole living in its core,Â giving astronomers the best idea yet as to where supermassive black holes come from. Omega Centauri might hold one of the most profound secrets asÂ to how the largest objects in the observable universe are born…

Two thousand years ago, Omega Centauri was classified as a single star by Ptolemy. Edmond Halley studied this “star” but thought it looked a bit diffuse and re-classified it as a nebula in 1677. Then, in the 1830s, John Herschel was the first astronomer to realize this “nebula” was actually a galaxy, a globular cluster galaxy. But now, new observations by the Hubble Space Telescope (HST) reveal that this “globular cluster” isn’t what it seems… it’s actually a dwarf galaxy, stripped of its outer stars, some 17,000 light years away.

See an observation video zooming into the location of Omega Centauri in the constellation of Centaurus.

So what led to astronomers thinking there was something strange about this cosmic collection of stars? It rotates faster than other globular clusters, it is strangely flat and it contains stars of many generations (globular clusters usually contain stars of one generation). These reasons plus the fact Omega Centauri is ten times bigger than the largest globular clusters have led scientists to believe that this was no ordinary galaxy.

The main theory is that this unlucky galaxy may have crashed into the Milky Way in the distant past, shedding its outermost stars during the collision. This explains the lack of stars in its outer region. But why is it rotating so quickly, especially in the center?

These stunning images were taken by the NASA/ESA Hubble Space Telescope, which continues to do amazing science after 18 years in orbit. Combined with ground-based observations by the Gemini South telescope in Chile, astronomers have been able to deduce that a black hole may be at the root of a lot of the anomalies seen in Omega Centauri.

The research carried out at the Max-Planck Institute for Extraterrestrial Physics (in Garching, Germany), headed by Eva Noyola, shows stars near the center of Omega Centauri orbiting something very fast. In fact, this something is invisible for a reason. Calculating this invisible object’s mass, it is most likely that the group are observing an intermediate-size black hole with the mass of 40,000 solar masses. They have investigated other possibilities, perhaps the fast-orbiting stars could be accelerated by the collective mass of small, weakly radiating bodies such as white dwarves, or the orbiting stars’ have highly elliptical orbits and the point of closest approach is currently being observed, giving the impression they are going faster. However, the intermediate-size black hole theory appears to fit the situation far better.

This is a highly significant discovery, as so far there has been little linking theÂ smaller, stellar black holes with the supermassive ones that sit in the center of large galaxies such as our own. There have been many theories put forward about how these huge black holes may have formed, but to find an intermediate-sized black hole may be the missing link and will help astrophysicists understand how supermassive black holes are “seeded” in the first place.

“This result shows that there is a continuous range of masses for black holes, from supermassive, to intermediate-mass, to small stellar mass types […] We may be on the verge of uncovering one possible mechanism for the formation of supermassive black holes. Intermediate-mass black holes like this could be the seeds of full-sized supermassive black holes.” – Eva Noyola.

Source: SpaceTelescope.org

March 28, 2008December 26, 2015 by Nancy Atkinson

Planet Formation Revealed?

ab-aurigaie-disc-of-material.thumbnail.jpg

One of the biggest unresolved questions of planet formation is how a thick disc of debris and gas surrounding young stars eventually evolves into a thin, dusty region with planets. This entire process, of course, has never actually been observed. But recently, and for the first time, a group of astrophysicists produced an image of material surrounding a star which seems to be coalescing into a planet.

The image was produced from a coronagraph attached to a telescope in Hawaii. It shows a horseshoe-shaped void in the disc of materials surrounding the star AB Aurigae, with a bright point appearing as a dot in the void.

“The deficit of material could be due to a planet forming and sucking material onto it, coalescing into a small point in the image and clearing material in the immediate surroundings,” said researcher Ben Oppenheimer, an astrophysicist at the American Museum of Natural History in New York. “It seems to be indicative of the formation of a small body, either a planet or a brown dwarf.”

A brown dwarf is considered a star that’s not massive enough to generate the thermonuclear fusion to create an actual star.

From what we know about planet formation, planets seem to be natural by-product of stars. But how does all this happen? Stars form when clouds of gas and dust contract under gravity, and if thereâ€™s enough compression and heat, sooner or later a nuclear reaction is triggered, and voilÃ : a star. If thereâ€™s any left-over material surrounding the young star, eventually the disc of dust and/or gas may congeal into planets. But the details of this process are unknown.

AB Aurigae is a well-studied star. It’s young, between one and three million years old, and can provide information on how stars and objects that orbit them form. And scientists hope that by studying this star, we can learn more about how planets form from the initial thick, gas-rich disk of debris that surrounds young stars. The observation of stars slightly older than AB Aurigae shows that at some point the gas is removed, but no one knows how this happens. AB Aurigae could be in an intermediate stage, where the gas is being cleared out from the center, leaving mainly dust behind.

“More detailed observations of this star can help solve questions about how some planets form, and can possibly test competing theories,” says Oppenheimer. And if this object is a brown dwarf, our understanding of them must be revamped as brown dwarfs are not believed to form in circumstellar materials, Oppenheimer said.

Original New Source: National Science Foundation Press Release

March 28, 2008December 26, 2015 by Ian O'Neill

13.73 Billion Years – The Most Precise Measurement of the Age of the Universe Yet

NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) has taken the best measurement of the age of the Universe to date. According to highlyÂ precise observations of microwave radiation observed all over the cosmos, WMAP scientists now have the best estimate yet on the age of the Universe: 13.73 billion years, plus or minus 120 million years (that’s an error margin of only 0.87%… not bad really…).

The WMAP mission was sent to the Sun-Earth second Lagrangian point (L₂), located approximately 1.5 million km from the surface of the Earth on the night-side (i.e. WMAP is constantly in the shadow of the Earth) in 2001. The reason for this location is the nature of the gravitational stability in the region and the lack of electromagnetic interference from the Sun. Constantly looking out into space, WMAP scans the cosmos with its ultra sensitive microwave receiver, mapping any small variations in the background “temperature” (anisotropy) of the universe. It can detect microwave radiation in the wavelength range of 3.3-13.6 mm (with a corresponding frequency of 90-22 GHz). Warm and cool regions of space are therefore mapped, including the radiation polarity.

This microwave background radiation originates from a very early universe, just 400,000 years after the Big Bang, when the ambient temperature of the universe was about 3,000 K. At this temperature, neutral hydrogen atoms were possible, scattering photons. It is these photons WMAP observes today, only much cooler at 2.7 Kelvin (that’s only 2.7 degrees higher than absolute zero, -273.15Â°C). WMAP constantly observes this cosmic radiation, measuring tiny alterations in temperature and polarity. These measurements refine our understanding about the structure of our universe around the time of the Big Bang and also help us understand the nature of the period of “inflation”, in the very beginning of the expansion of the Universe.

It is a matter of exposure for the WMAP mission, the longer it observes the better refined the measurements. After seven years of results-taking, the WMAP mission has tightened the estimate on the age of the Universe down to an error margin of only 120 million years, that’s 0.87% of the 13.73 billion years since the Big Bang.

“Everything is tightening up and giving us better and better precision all the time […] It’s actually significantly better than previous results. There is all kinds of richness in the data.” – Charles L. Bennett, Professor of Physics and Astronomy at Johns Hopkins University.

This will be exciting news to cosmologists as theories on the very beginning of the Universe are developed even further.

Source: New York Times

March 23, 2008December 26, 2015 by Ian O'Neill

Light Echos from 400 Year Old Supernova Observed for the First Time (Time-lapse Video)

Its observations like these that really give us an idea about how big the cosmos actually is. A star in a small galaxy called the Large Magellanic Cloud (LMC), some 160,000 light years from Earth, exploded as a massive supernova 400 years ago (Earth years that is). Combining the observations from an X-ray observatory and an optical telescope, scientists are currently observing the reflected light off galactic dust, only just reaching the Earth hundreds of years after the explosion…

Shakespeare’s first run the stage production, Hamlet, will have been in full-swing. Galileo might have been experimenting with his first telescope. Guy Fawkes could have been plotting to blow up the British parliament. These events all occurred around the beginning of the 17th Century when a bright point of light may have been seen in the night sky. This point of light, in the Large Magellanic Cloud (LMC), is a massive star exploding, ending its life in a powerful supernova.

Now, 400 years after the event, we can see a “supernova remnant” (SNR), and this particular remnant is known as SNR 0509-67.5 (not very romantic I know). The remnant of superheated gas slowly expands into space and still emits X-rays of various energies. The 400 year old explosion has even been imaged in great detail by the Chandra Observatory currently observing space in X-ray wavelengths. Analysis of the SNR indicates that it was most likely caused by a Type Ia supernova after analysis of the composition of the gases, in particular the quantities of silicon and iron, was carried out. It is understood that the supernova was caused when a white dwarf star in a binary system reached critical mass, became gravitationally unstable (due to fusion reactions in the core stopping) and exploded.

When SNR 0509-67.5 exploded all those years ago, it will have radiated optical electromagnetic radiation (optical light) in all directions of space. Now, for the first time, optical Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory (Chile) has observed reflected light from within the LMC originating from the supernova, 400 years after the event. Using the (reflected) optical light and X-ray emissions directly from the supernova remnant, scientists have been able to learn just how much energy was generated by the explosion.

Astronomers have even assembled a time-lapse video from observations of the light “echo” from 2001 to 2006. Although there are only five frames to the video, you can see the location of the reflected light change shape as different volumes of galactic dust are illuminated by the flash of supernova light. In each progressive frame, the clouds of gas that become illuminated will be further and further away from us, we are effectively looking further back in time as the light “echoes” bounce off the galactic matter.

An amazing discovery.

Source: Chandra X-ray Observatory

March 20, 2008December 26, 2015 by Ian O'Neill

Biggest Ever Cosmic Explosion Observed 7.5 Billion Light Years Away

A record-breaking gamma ray burst was observed yesterday (March 19th) by NASA’s Swift satellite. After red-shift observations were analysed, astronomers realized they were looking at an explosion half-way across the Universe, some 7.5 billion light years away. This means that the burst occurred 7.5 billion years ago, when the Universe was only half the age it is now. This shatters the record for the most distant object that can be seen with the naked eye…

Gamma ray bursts (GRBs) are the most powerful explosions observed in the Universe, and the most powerful explosions to occur since the Big Bang. A GRB is generated during the collapse of a massive star into a black hole or neutron star. The physics behind a GRB is highly complex, but the most accepted model is that as a massive star collapses to form a black hole, the in falling material is energetically converted into a blast of high energy radiation. It is thought the burst is highly collimated from the poles of the collapsing star. Any local matter downstream of the burst will be vaporized. This has led to the thought that historic terrestrial extinctions over the last hundreds of millions of years could be down to the Earth being irradiated by gamma radiation from such a blast within the Milky Way. But for now, all GRBs are observed outside our galaxy, out of harms way.

This record-breaking GRB was observed by the Swift observatory (launched into Earth orbit in 2004) which surveys the sky for GRBs. Using its Burst Alert Telescope (BAT), the initiation of an event can be relayed to Earth within 20 seconds. Once located, the spacecraft turns all its instruments toward the burst to measure the spectrum of light emitted from the afterglow. This observatory is being used to understand how GRBs are initiated and how the hot gas and dust surrounding the event evolves.

“This burst was a whopper; it blows away every gamma ray burst we’ve seen so far.” – Neil Gehrels, Swift principal investigator, NASA Goddard Space Flight Center, Greenbelt, Md.

This particular GRB was observed in the constellation of BoÃ¶tes at 2:12 a.m. (EDT), March 19th. Telescopes on the ground and in space quickly turned to BoÃ¶tes to analyse the afterglow of the burst. Later in the day, the Very Large Telescope in Chile and the Hobby-Eberly Telescope in Texas measured the burst’s redshift at 0.94. From this measure, scientists were able to pinpoint our distance from the explosion. This red shift corresponds to a distance of 7.5 billion light years, signifying that this huge GRB happened 7.5 billion years ago, over half the distance across the observable universe.

Source: NASA

March 16, 2008December 26, 2015 by Ian O'Neill

When Black Holes Explode: Measuring the Emission from the Fifth Dimension

Exploding primordial black holes could be detected (credit: Wired.com)

Primordial black holes are remnants of the Big Bang and they are predicted to be knocking around in our universe right now. If they were 10¹²kg or bigger at the time of creation, they have enough mass to have survived constant evaporation from Hawking radiation over the 14 billion years since the beginning of the cosmos. But what happens when the tiny black hole evaporates so small that it becomes so tightly wrapped around the structure of a fifth dimension (other than the “normal” three spatial dimensions and one time dimension)? Well, the black hole will explosively show itself, much like an elastic band snapping, emitting energy. These final moments will signify that the primordial black hole has died. What makes this exciting is that researchers believe they can detect these events as spikes of radio wave emissions and the hunt has already begun…

Publications about primordial black holes have been very popular in recent years. There is the possibility that these ancient singularities are very common in the Universe, but as they are predicted to be quite small, their effect on local space isn’t likely to be very observable (unlike younger, super-massive black holes at the centre of galaxies or the stellar black holes remaining after supernovae). However, they could be quite mischievous. Some primordial black hole antics include kicking around asteroids if they pass through the solar system, blasting through the Earth at high velocity, or even getting stuck inside a planet, slowly eating up material like a planetary parasite.

But say if these big bang relics never come near the Earth and we never see their effect on Earth (a relief, we can do without a primordial black hole playing billiards with near Earth asteroids or the threat of a mini black hole punching through the planet!)? How are we ever going to observe these theoretical singularities?

Now, the ultimate observatory has been realized, but it measures a fairly observable cosmic emission: radio waves. The Eight-meter-wavelength Transient Array (ETA) run by Virginia Tech Departments of Electrical & Computer Engineering and Physics, and the Pisgah Astronomical Research Institute (PARI), is currently taking high cadence radio wave observations and has been doing so for the past few months. This basic-looking antenna system, in fields in Montgomery County and North Carolina, could receive emissions in the 29-47 MHz frequencies, giving researchers a unique opportunity to see primordial black holes as they die.

Interestingly, if their predictions are correct, this could provide evidence for the existence of a fifth dimension, a dimension operating at scales of billionths of a nanometer. If this exotic emission can be received, and if it is corroborated by both antennae, this could be evidenceÂ of the string theory prediction that there are more dimensions than the four we currently understand.

“The idea we’re exploring is that the universe has an imperceptibly small dimension (about one billionth of a nanometer) in addition to the four that we know currently. This extra dimension would be curled up, in a state similar to that of the entire universe at the time of the Big Bang.” – Michael Kavic, project investigator.

As black holes are wrapped around this predicted fifth dimension, as they slowly evaporate and lose mass, eventually primordial black holes will be so stressed and stretched around the fifth dimension that the black hole will die, blasting out emissions in radio wave frequencies.

“String theory requires extra dimensions to be a consistent theory. String theory suggests a minimum of 10 dimensions, but weâ€™re only considering models with one extra dimension.” – Kavic

When the Large Hadron Collider goes online in May, it is hoped that the high energies generated may produce mini-black holes (amongst other cool things) where research can be done to look for the string theory extra dimensions. But the Eight-meter-wavelength Transient Array looking for the death of “naturally occurring” primordial black holes is a far less costly endeavour and may achieve the same goal.

Here’s an article on a theory that there could be 10 dimensions.

Source: Nature

February 25, 2008April 26, 2016 by Ian O'Neill

Record Breaking “Dark Matter Web” Structures Observed Spanning 270 Million Light Years Across

It is well documented that dark matter makes up the majority of the mass in our universe. The big problem comes when trying to prove dark matter really is out there. It is dark, and therefore cannot be seen. Dark matter may come in many shapes and sizes (from the massive black hole, to the tiny neutrino), but regardless of size, no light is emitted and therefore it cannot be observed directly. Astronomers have many tricks up their sleeves and are now able to indirectly observe massive black holes (by observing the gravitational, or lensing, effect on light passing by). Now, large-scale structures have been observed by analyzing how light from distant galaxies changes as it passes through the cosmic web of dark matter hundreds of millions of light years across…

Dark matter is believed to hold over 80% of the Universe’s total mass, leaving the remaining 20% for “normal” matter we know, understand and observe. Although we can observe billions of stars throughout space, this is only the tip of the iceberg for the total cosmic mass.

Using the influence of gravity on space-time as a tool, astronomers have observed halos of distant stars and galaxies, as their light is bent around invisible, but massive objects (such as black holes) between us and the distant light sources. Gravitational lensing has most famously been observed in the Hubble Space Telescope (HST) images where arcs of light from young and distant galaxies are warped around older galaxies in the foreground. This technique now has a use when indirectly observing the large-scale structure of dark matter intertwining its way between galaxies and clusters.

Astronomers from the University of British Columbia (UBC) in Canada have observed the largest structures ever seen of a web of dark matter stretching 270 million light years across, or 2000 times the size of the Milky Way. If we could see the web in the night sky, it would be eight times the area of the Moons disk.

This impressive observation was made possible by using dark matter gravity to signal its presence. Like the HST gravitational lensing, a similar method is employed. Called “weak gravitational lensing”, the method takes a portion of the sky and plots the distortion of the observed light from each distant galaxy. The results are then mapped to build a picture of the dark matter structure between us and the galaxies.

The team uses the Canada-France-Hawaii-Telescope (CFHT) for the observations and their technique has been developed over the last few years. The CFHT is a non-profit project that runs a 3.6 meter telescope on top of Mauna Kia in Hawaii.

Understanding the structure of dark matter as it stretches across the cosmos is essential for us to understand how the Universe was formed, how dark matter influences stars and galaxies, and will help us determine how the Universe will develop in the future.

“This new knowledge is crucial for us to understand the history and evolution of the cosmos […] Such a tool will also enable us to glimpse a little more of the nature of dark matter.” – Ludovic Van Waerbeke, Assistant Professor, Department of Physics and Astronomy, UBC

Source: UBC Press Release

January 21, 2008December 26, 2015 by Ian O'Neill

Forget Black Holes, How Do You Find A Wormhole?

An artists impression of what it would look like inside a wormhole. Pretty. (credit: Space.com)

Finding a black hole is an easy task… compared with searching for a wormhole. Suspected black holes have a massive gravitational effect on planets, stars and even galaxies, generating radiation, producing jets and accretion disks. Black holes will even bend light through gravitational lensing. Now, try finding a wormhole… Any ideas? Well, a Russian researcher thinks he has found an answer, but a highly sensitive radio telescope plus a truckload of patience (I’d imagine) is needed to find a special wormhole signature…

Wormholes are a valid consequence of Einstein’s general relativity view on the universe. A wormhole, in theory, acts as a shortcut or tunnel through space and time. There are several versions on the same theme (i.e. wormholes may link different universes; they may link the two separate locations in the same universe; they may even link black and white holes together), but the physics is similar, wormholes create a link two locations in space-time, bypassing normal three dimensional travel through space. Also, it is theorized, that matter can travel through some wormholes fuelling sci-fi stories like in the film Stargate or Star Trek: Deep Space Nine. If wormholes do exist however, it is highly unlikely that you’ll find a handy key to open the mouth of a wormhole in your back yard, they are likely to be very elusive and you’ll probably need some specialist equipment to travel through them (although this will be virtually impossible).

Alexander Shatskiy, from the Lebedev Physical Institute in Moscow, has an idea how these wormholes may be observed. For a start, they can be distinguished from black holes, as wormhole mouths do not have an event horizon. Secondly, if matter could possibly travel through wormholes, light certainly can, but the light emitted will have a characteristic angular intensity distribution. If we were viewing a wormhole’s mouth, we would be witness to a circle, resembling a bubble, with intense light radiating from the inside “rim”. Looking toward the center, we would notice the light sharply dim. At the center we would notice no light, but we would see right through the mouth of the wormhole and see stars (from our side of the universe) shining straight through.

For the possibility to observe the wormhole mouth, sufficiently advanced radio interferometers would be required to look deep into the extreme environments of galactic cores to distinguish this exotic cosmic ghost from its black hole counterpart.

However, just because wormholes are possible does not mean they do exist. They could simply be the mathematical leftovers of general relativity. And even if they do exist, they are likely to be highly unstable, so any possibility of traveling through time and space will be short lived. Besides, the radiation passing through will be extremely blueshifted, so expect to burn up very quickly. Don’t pack your bags quite yet…

Source: arXiv publication

January 21, 2008December 26, 2015 by Nicholos Wethington

Flying Telescope Passes Its First Stage of Tests

Telescopes on the ground â€“ while having all sorts of good qualities â€“ have the disadvantage of peering through the whole of the atmosphere when looking at the stars. Space-based telescopes like Hubble are an effective way around this, but launching a telescope into space and maintaining it is not exactly cheap. What about something in between the two?

This is where SOFIA (Stratospheric Observatory for Infrared Astronomy) flies in. SOFIA is a converted 747SP airliner that used to carry passengers for United Airlines and Pan Am, but now only has one voyager: an infrared telescope.

SOFIA recently completed the first phase of flight tests to determine its structural integrity, aerodynamics and handling abilities. This first series of tests were done with the door through which the telescope will peer closed, and open-door testing will begin in late 2008.

What makes SOFIA valuable is its ability to fly high in the stratosphere for observations, at around 41,000 feet (12.5km). This eliminates the atmosphere in between the ground and space, which causes turbulence in the light coming through, and also absorbs almost completely some wavelengths of infrared light.

Cloudy nights, normally the bane of observational astronomy, will not impede the ability of SOFIA. Other advantages are that scientists will be able to add specialized observing instruments for specific observations, and fly to anywhere in the world.

The telescope is 10 feet across, and weighs around 19 tons. It will look through a 16-foot high door in the fuselage to study planetary atmospheres, star formation and comets in the infrared spectrum.

During this stage of testing, the ability of the telescope to compensate for the motion and vibrations of the airplane was checked. After the first open-door tests are run this year, the mobile observatory will begin making observations in 2009, and will be completely operational in 2014.

SOFIA is a cooperation between NASA, who will maintain the plane, and the German Aerospace Center, who built and will maintain the telescope.

Source: NASA Press Release

January 4, 2008December 26, 2015 by Nancy Houser

Meteor Shower Throws Over 100 Meteors per Hour

With over 100 meteors per hour, the Quadrantid Meteor Shower is one of the latest mergers between Google and NASA, a major asset to space research due to their successful combination of ideas and plans. This peak shower began around 0200 UTC on Friday morning, January 4th, with the jet owned by the founders of Mountain View-based Google flying amongst big science players, such as the SETI research team.

To see this spectacular sight and to partake in a scientific mission, Google carried a team of NASA scientists and their high-technology instruments on board the Google owned Gulfstream V jet, which left the Mineta San Jose International Airport on Thursday late afternoon about 4:30 p.m. Plans were made for a ten-hour flight over the Arctic, returning to home base when the meteor shower mission was accomplished with the resulting data.

The GOOG Google.com Stock Message Board is full of the things that Google has been doing to improve the worldâ€”a real biggie was to develop a cheaper solar, wind power for Earthâ€”excellent idea from a company whose corporate motto is to â€œdo not be evil.â€? That plan involved the creation of a research group to develop energy sources that was a cheaper renewable alternative which focuses on solar, wind and any other forms of power through the Renewable Energy â€œCheaper Than Coalâ€? project. And of course, lowering Google’s power bill was top of the list before anyone else as a huge incentive.

Last September, as most are aware of, NASA and Google had launched a $2.6 million dollar agreement to let the Google co-founders house their aircraft at Moffett Field while NASA was to be allowed to use it for their science work, such as that of the Quadrantid Meteor Shower. Other prospective plans for Google are to hand out $30 million dollars to any company that successfully comes up with a plan to bring people to the moon. Another plan is to fund a space race through Google’s Lunar X Prize competition.

Original Source: NASA News Release