Bellatrix Orionis

Image Credit: NASA/JPL/University of Arizona

NASA’s Galileo spacecraft sent back this image of Jupiter’s moon Europa which shows the surface crust is made up of blocks.  It’s thought tat the blocks have broken apart and drifted into new positions. This is considered the best geological evidence so far that Europa has had a subsurface ocean at some point in it’s past history.

This data and the fact that Europa has a magnetic field has lead scientists to believe an ocean is most likely present today.

In this false color image, reddish-brown areas represent non-ice material resulting from geologic activity.  White areas are material ejected during the formation of the Pwyll impact crater.  Whilst icy plains are shown in blue tones to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue).  Long, dark lines are ridges and fractures in the crust, some of which are more than 1,850 miles long.

Credit: NASA/Swift/Stefan Immler

A team of international astronomers using NASA’s Swift satellite have found a gamma-ray burst from a star which died when the univers was just 630 million year old, which is approximately less than 5% of it’s present age.  It’s thought to be the most distant explosion ever seen and has been named GRB 090423.

Scientists have dubbed this a true blast from the past.

The Swift satellite discovered the 10 second gamma ray burst on 23 April.  A fading x-ray glow was observed but no visible light.

It’s thought that the gamma ray burst occured due to the explosion of a massive star and there is also the posibility of a black hole forming.

Gamma ray bursts are the most brilliant explosions seen in the Universe.  They usually appear when a massive star runs out of nuclear fuel and collapse in on themselves.  When this happens they become either a black hole or a neutron star.  When this happens gas jets smash through the star and shoot into space.  The gas jet the stikes any gas which was shed by the star during the explosion heating it up which then glows for a short time.

Within 3 hours of the burst astronomers at the University of Leicester had detected an infrared source at the same position using the United Kingdon Intrared Telescope (UKIT) on Mauna Kea, Hawaii.

The explosion is thought to be 13.035 billion light years away.  This was confirmed by observations using the European Very Large Telescope and the Galileo National Telescope.

Around the world in 80 telescopes has now put the archived videos on the web for your viewing pleasure.  They can be found at ESO-Special Events.  Telescopes which took part in the event include:

• Gemini North Telescope
• Subaru Telescope, National Astronomical Observatory of Japan (NAOJ)
• United Kingdom Infrared Telescope (UKIRT)
• W M Keck Observatory
• James Clerk Maxwell Telescope (JCMT)
• Canada-France-Hawaii Telescope (CFHT)
• Submillimeter Array
• Caltech Submillimeter Observatory
• MOA Telescope
• Anglo-Australian Telescope (AAT)
• GEO600, the German-British Gravitational Wave Detector
• NAOJ Nobeyama, Nobeyama Radio Observatory (NRO)
• Gunma Astronomical Observatory
• Okayama Astrophysics Observatory
• Themis
• SolarLab
• Quijote
• ESA’s XMM-Newton Xray Observatory and Integral Gamma Ray Observatory
• Atacama Pathfinder Experiment (APEX)
• Atacama Large Millimeter/submillimeter Array (ALMA)
• European VLBI Network (EVN)
• ASTRON Westerbork Synthesis Radio Telescope (WSRT)
• LOFAR the LOW Frequency Array of ASTRON
• Virgo Gravitational Wave Detector at the European Gravitational Observatory
• The University of Manchester’s Jodrell Bank Observatory
• NASA/ESA Hubble Space Telescope
• The Very Large Array (VLA)
• SOHO (Solar and Heliospheric Observatory) and TRACE (Transitional Region and Coronal Explorer)

On the 26 April 1920 a debate took place between two American astronomers, Heber Curtis and Harlow Shapley.  Curtis argued that fuzzy patches in the night sky called ’spiral nabulae’ are separate galaxies or ‘island universes’, lying far away from us.  Curtis claimed that our own galaxy was less than 30,000 lightyears wide, with the Sun located near the centre.  Shapley agued that the spiral nebulae were merely nearby gas clouds inside the Milky Way.  He also claimed the Universe was composed of only one big galaxy more than 300,000 lightyears wide, with the Sun lying far away from the galactic centre.

The debate was resolved in the mid 1920’s by Edwin Hubbles work which involved pinpointing Cephid Variables in M31 (a spiral nebula).  His work showed that the distance to M31 is much greater than Shapley had imagined as M31 is indeed an ‘island universe’ now better known as the Andromeda Galaxy.

It’s now known that Curtis was right about other galaxies existing, whilst Shapley’s idea about the location of the Sun was better.  Both astronomers were wrong about the size of the Milky Way.  Astronomers current predictions have our galaxy at approx 100,000 lightyears wide.

Credit: NASA/CXC/SAO/D.Patnaude et al.

A time lapse movie has been created from images taken by NASA’s Chandra X-ray Observatory of the supernova remnant Cassiopeia A.

Cassiopeia A is the remains of a star thought to have exploded about 320 years ago.  Also called Cas A, it’s thought to be the youngest known supernova remnant in our galaxy (the Milky Way) and is 10,000 light years away in the constellation Cassiopeia.  This means that Cas A actually blew up 10,000 years before the light reached us here on earth during the late 1600s.

The fantastic colours seen in the image are from chemical elements glowing, for example the blue fragments are richest in oxygen and the red material is rich in sulpher.

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

During the last 19 years the Hubble Space Telescope has taken dozens of fantastic images, such as this one showing galaxies having a ‘close encounter’.  The blue streamer between the two galaxies is a spiral arm of newborn blue stars.  This happens when two galaxies interact and gravitationally tug at each other.

The nuclei of both colliding galaxies can be seen in the process of merging.  In the image the blue bridge looks like it’s connecting to a third galaxy.  This galaxy is actually in the background and does not connect at all.  Due to Hubbles fantastic optics astronomers are able to sort out which objects are foreground and background.

This image was issued to celebrate the 19th anniversary of the launch of the Hubble Space Telescope.

Over the last 19 years Hubble has taken 570,000 images of 29,000 celestial objects and more than 880,000 observations.

Want to find out if it’s Io or Europa you’re looking at?  Then check out this handy little application from the nice people over at the BBC Sky at Night magazine.  It shows you which moons you’ll be able to see depending on your observing equipment

Pictured is a Hubble image showing what happens when there is a galactic battle royal.  Data from NASA’s Chandra X-ray Observatory, Hubble Space Telescope and the Keck Observatory in Hawaii have allowed astronomers to define the three dimensional geomatory as well as the motion in the system MACS J0717.5+3745 (shortened to MACS J0717).  MACS J0717 is a cluster of galaxies which are about 5.4 billion light years from Earth and can be located in the constellation Auriga.

Credit: NASA, ESA, and J. Madrid (McMaster University)

The flare is coming from HST-1 which is a clump of matter embedded in the jet of hot gas produced by a supermassive black hole in the middle of M87.  HST-1 is currently so bright that it’s even outshining the core of M87.  The black hole at the centre of M87 is thought to be the most massive found to date.

HST-1 has suprised astronomers by steadily brightening for several years, fading and then brightening again.

The Hubble Space Selescope has been used to observe this object for seven years now and has provided detailed untraviolet light views of  the events.  Other telescopes such as the Chandra X-ray Observatory have also been monitoring HST-1.  The object was first discovered by Hubble astronomers in 1999.  The gas knot is 214 light years from the galaxy’s core.

M87 is 54 million light years away in the Virgo Cluster which is a region with a high density of galaxies.  It’s hoped that he flare up may provide insights into the variability of black hole jets in distant galaxies which are often difficult to study due to the imense distances.

Even though many observations have been made astronomers are still unsure as to what is causing the brightening.  One explanation is that the jet is hitting a gas cloud or dust lane and then glows due to the collision.  Another suggestion is that the jet’s magnetic field lines are squeezed together, which creates a huge amount of energy.  This is a similar way to how solar flares develop on the Sun and also generate the auroras on Earth.

Astronomers are hoping that continued observations will expain what is causing the flaring an give a greater understanding of the jet.

Fancy an observational challenge?  Got a large telescope? (>150mm reflector/>100mm refractor) Then check out the brightest known quasar within visible wavelengths – 3C 273.  The quasar can be found in the constellation of Virgo and is approximately 2.44 billion light years away from us, with a variable magnitude (brightness) is +12.8

Quasars are very powerful active nuclei of distant galaxies and are thought to be the result of evergy radiating from matter collecting around a supermassive black hole.