Galactic roles, a cosmic puzzle and a dusty answer

Giant galaxies are the ones that catch the space enthusiast’s eye, with their spiral patterns or cigar-like blobs in images taken with large telescopes. But their more elusive and tiny cousins, the dwarf galaxies, played a major role in switching on the Universe, it turns out.

A supernova blast
An artistic rendition of dust formation around a supernova explosion. Observations with the VLT in Chile show that this happens in two stages. Image credit: ESO/M. Kornmesser

Fresh evidence reveals that, despite their small size, these collections of stars, which are individually around 1,000 times less massive than our own Milky Way, helped end a long period of darkness, shortly after the Big Bang, before the first stars began to glow.

This period, called the “epoch of re-ionisation”, was completed about one billion years after the Big Bang and left us with the Universe much as it still looks today. You can read my full report on the new findings over at Sen.

There is a mystery to solve too, for cosmologists studying the Universe. It has been found that a particularly high proportion of cosmic rays are coming from a zone in space within Ursa Major, the constellation of the Great Bear.

Cosmic rays are one of the most energetic yet mysterious phenomena in the Universe, and are particles rather than rays. Their source is generally uncertain, but it is thought they are emited by jets from active galaxies with supermassive black holes, the most powerful supernovae or gamma ray bursts.

Again, you can read more about this cosmic conundrum in my news story over at Sen.

Talking of supernovae, new research shows that the clouds of cosmic dust that provide building material for new star systems are produced in huge quantities by violent supernova explosions.

These dust grains, made up of elements such as carbon, silicon, oxygen, iron, and magnesium, are surprisingly even able to survive the huge shockwaves that follow these huge stellar explosions.

Read my report at Sen on how a team of astronomers has, for the first time, watched as stardust is formed, by monitoring a supernova’s fade with the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

Closer to home, planet Mars is never far from the space headlines. Much evidence has already been found to show that there was a lot of water there, billions of years ago.

Now an overall insight into how water modified the martian surface has been provided by a new geological map of its ancient highland regions, produced by the Planetary Science Institute, at Tucson, Arizona.

It helps show the sequence of events as water spread across plains and high areas of Mars, as my full report for Sen describes.

Still in the Solar System, NASA’s MESSENGER probe is best known for its studies of Mercury, which it has been orbiting since March 2011. The probe has sent home more than 200,000 images of that innermost rocky world.

What you may not know is that it has also used its unique position in space to make close-up studies of activity on the Sun and the effects in that region of the Solar System of space weather. Read my story explaining how over at Sen.

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By Paul Sutherland

Paul Sutherland has been a professional journalist for nearly 40 years. He writes regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy, plus he has authored three books on astronomy and contributed to others.

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