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06/11/08

- It always pours....

Hot on the heels of the stupendous Hubble Space Telescope image of an extrasolar planet, the ESO has imaged a planet around another star although this image isn't in visible light but infrared.

Using the Very Large Telescope in Chile, a team of astronomers have found a planet around the very well studied star Beta Pictoris. The planet is estimated to be eight times bigger than Jupiter and the distance from the star to be almost as much as the distance between Saturn and the Sun.

Beta Pictoris is only 12 million years old and is still surrounded by a debris disc. This disc was known to exist at least 25 years ago when it was imaged in 1984. The disc contains a warp and this is one piece of evidence for the definite presence of a large planet.

The planet was revealed by utilising advanced adaptive optics technology. To prove that the planet was real and not an imaging artefact, many tests were carried out as well as the planet appearing in multiple images.

More studies and observations will be needed to prove the planet actually orbits Beta Pictoris and isn't a foreground or background object that happens to share the line of sight.

The dramatic picture shows Beta Pictoris as a tiny white dot at the centre of the circle with the bright blue blob being the planet. The infrared image shows differences in temperature in the debris discs, the outer parts are cooler than the inner parts. The white ring at top right is the orbit of Saturn and comparing it to the planet shows that it has a similar orbit. The central blue circle is an imaging artefact completely unrelated to the star.

     
02/12/08

- First ever visible light image of an exoplanet!

Standing in the cold outdoors under the majestic night sky, you might be inclined to wonder if any of the stars that you can see have planets around them. One of the stars that can be seen during autumn is Fomalhaut, the 18th brightest star in the night sky.

The Hubble Space Telescope has found a planet around Fomalhaut, although this discovery pales in comparison to achieving what some people deemed impossible, actually imaging a planet around another star! What makes this even more special is that this is the very first time an extrasolar planet has been imaged in visible light!

As with other momentous achievements, the imaging of the planet wasn't quick and easy. Astronomer Paul Kalas repeatedly imaged Fomalhaut with the HST for eight years and has now made history!

Fomalhaut is a quick jaunt away at a distance of 25 light years and is surrounded by a ring of gas and dust. This gas and dust is what planets form out of and our Sun would have most likely had this type of feature 4.5 billion years ago.

Paul Kalas was certain of the existence of the planet due to perturbations in the ring. Images taken in 2005 with the HST showed a sharp edge to the ring and it seemed evident that the ring of material was being affected by another object. The only thing the object could be was a planet.

Pictures taken apart in 2004 and 2006 clearly show the planet moving. From this it is known that the planet is 11 billion miles away from Fomalhaut and has an orbit of 872 years.

The picture shows the star being blacked out by a coronagraph mask, this blocked the overwhelming light of blazing Fomalhaut and this allowed the planet to be visible. The ring of dust can be seen around the star and is affected by the gravity of the planet.

Almost 20 years after it was launched, the Hubble Space Telescope has achieved a milestone in astronomy and the next decade will open the floodgates for more direct pictures of exoplanets with new advanced observatories such as the James Webb Space Telescope, scheduled for launch in 2013. The next frontier is discovering exomoons around exoplanets, they will hopefully be detected in the years to come.

     
28/11/08

- Another Mars discovery!

Mars has certainly been in the spotlight this year, are there no end to the surprises?

Underground glaciers of water ice have been discovered by the radar of the Mars Reconnaisance Orbiter. Now you might be thinking that they lie near the poles, they are in fact situated in the southern hemisphere! This is the largest collection of water ice found away from the poles.

The glaciers lie in the Hellas Basin and they extend from the edges of mountain ranges. One of them is so huge that it is three times larger than Los Angeles! They are shielded by a huge layer of rocky debris and they would vapourise if exposed to the atmosphere. The picture is an artists impression.

     
21/11/08

- The fire has burnt out

The Phoenix lander has ceased communicating with Earth, so NASA has now announced the Phoenix lander mission as over.

Phoenix made some amazing discoveries while it was functional such as the pivotal discovery of water ice. Scientists are eager to analyse all the data and see what else Phoenix might have found.

Many conditions have contributed to the shutdown of Phoenix. The main one is the sharp drop in the amount of sunlight at the north pole, Phoenix is unable to gain any power from its solar panels. The other factor are huge dust storms cutting off the supply of sunlight.

There is an incredibly tiny chance that Phoenix might come back online next year but this seems highly unlikely as it would be entombed in a block of ice due to the Martian winter.

     
31/10/08

- New probe to explore outer frontiers

With the exception of Pluto, the solar system has been meticulously observed and studied by a myriad number of probes in the past few decades. But there is one region that has been ignored, the outer parts of the solar system where the solar wind meets interstellar space.

The venerable duo of Voyager 1 and Voyager 2 have both acquired useful but limited data about the boundary between the solar wind and outer space. With the launch of a new probe on October 19, this region will no longer be a mystery.

The probe is called "Interstellar Boundary Explorer" or IBEX for short. The region it will scrutinise lies three times further than the distance to Pluto. Every six months, full sky maps will be made to determine what the edge of the solar system bubble looks like.

     
26/10/08

- Fermi makes unique discovery

The new gamma ray observatory Fermi has discovered an unexpected object, a pulsar that only emits gamma rays! Pulsars are created from the death of massive stars, they are neutron stars that spin at incredible speeds. Most of them emit radio waves but there have been some cases of pulsars emitting in other wavelengths.

Analysing the data has yielded important information about this rare type of object. One factor contributing to this was Fermi being able to detect one gamma ray every minute from the pulsar. From this, scientists calculated the rate of the pulsation, which is once every 316.86 milliseconds.

The pulsar is 10 000 years old and is situated in a relatively nearby supernova remnant called CTA 1, which is 4600 light years away in the constellation Cepheus. The picture shows the CTA 1 supernova in gamma rays with the white dot being the pulsar. The inset shows an illustration of the pulsar emitting two gamma ray beams.

     
12/10/08

- A flash bang star quake

While observing a star in June, the Swift satellite detected a sudden outburst of gamma rays that lasted a few seconds. Then a few days later the star flashed on and off 40 times in optical light! Then it went completely dark and dormant!

It is hypothesized that the star was a special type of star called a magnetar. These extremely rare stars have only been documented only a dozen times but it is highly likely there are many more lurking in the shadows of the Milky Way.

Magnetars are a type of neutron star, except they have magnetic fields a hundred times more powerful. Neutron stars spin rapidly so combine that with a super strong magnetic field and you have a recipe for disaster!

What happened was the stress induced crust snapped and this starquake released a reservoir of extra magnetic energy and this caused a spike in the activity of the star. This is something that probably happens at regular intervals of most likely a few decades altohugh more study is needed to confirm this. The picture on the left is an artistic impression.

     
06/10/08

- Drifting towards the darkness

What we see in the universe is nothing compared to what is undetectable, just as the universe doesn't conform to man made cosmological models, it always astounds and surprises humanity in ways we can't imagine.

A team of intrepid galactic explorers studying the background microwave radiation and galaxy clusters found that hundreds of galaxy clusters were mysteriously drifting towards one singular point. Most of the clusters in the sample are 6 billion light years away so this drift motion would have occured around about when the universe was half its current age.

Something is obviously causing the drift of the clusters but currently it is unknown what this force is but astronomers have given it the memorable imaginitive moniker of the "Dark Flow". This joins other cosmological mysteries such as dark matter and dark energy. The galaxy cluster in the picture is one of the hundreds that are part of the Dark Flow.