Mystery Solved. How We Get Ultra-Compact Dwarf Galaxies

This NASA/ESA Hubble Space Telescope image shows the dwarf galaxy M60-UDC1. Lying about 50 million light-years away, M60-UCD1 is a tiny galaxy with a diameter of 300 light-years — just 1/500th of the diameter of the Milky Way! Despite its size it is pretty crowded, containing some 140 million stars. The dwarf galaxy may actually be the stripped remnant of a larger galaxy that was torn apart during a close encounter with its neighbour, a massive galaxy called Messier 60. Circumstantial evidence for this comes from the recent discovery of a monster black hole, which is not visible in this image, at the centre of the dwarf. The black hole makes up 15 percent of the mass of the entire galaxy, making it much too big to have formed inside a dwarf galaxy.
Ultra Compact Dwarf Galaxy M60-UCD1 (Credit NASA/ESA and A.Seth)

I have been fascinated by galaxies for most of my adult life. I find it amazing that, just as we can ascertain the lifecycle of a tree by closely studying the trees in a forest, it is possible to study a sample of galaxies and understand galactic evolution.  A team of astronomers using the Gemini North Telescope have recently solved a long standing galactic mystery, namely how we get ultra-compact dwarf galaxies (UCDs to use their catchy acronym).

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SETI Researchers Just Got a $200 Million Gift to Search for Life

SETI Institute Logo
The SETI Institute

Among the many outstanding questions in science, ‘Are We Alone’ must be the one that captivates scientists and public alike.  I have very fond memories watching the SETI screensaver on my laptop churn through data while and wondering if the big peaks in the fascinating looking graphs meant something had been found! That was a good few years back now but the search for ET continues.  One such organisation spearheading the hunt is the SETI Institute and they have just announced a whacking great alien busting $200 million gift. 

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Astronomers are Hoping to Detect Gravitational Waves Coming from Supernova 1987A

This Hubble Space Telescope image shows Supernova 1987A within the Large Magellanic Cloud, a neighboring galaxy to our Milky Way.
Hubble Space Telescope image of SN1987A in the Large Magellanic Cloud (Credit : NASA)

A supernova explosion is a cataclysmic explosion that marks the violent end of a massive star’s life. During the event, the star releases immense amounts of energy, often outshining the combined light from all the stars in the host galaxy for a very brief period of time. The explosion produces heavy elements and spreads them out among the stars to contribute to the formation of new stars and planets. The closest supernova in recent years occurred in the Large Magellanic Cloud in 1987 (SN1987A) and now, a team of astronomers have searched through mountains of data to see if they can detect gravitational waves from the remnant. 

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Oops. Astronauts Lost a Tool Bag During a Spacewalk!

NASA astronauts Jasmin Moghbeli (top) and Loral O’Hara (bottom) team up during their first spacewalk for maintenance on the outside of the space station. Credit: NASA TV
NASA Astronauts Jasmin Moghbeli (top) and Loral O'Hara (bottom)

I know for a fact it’s one of the most annoying things that can happen.  I’ve done it lots; whether that be out at night with telescope or a bit of DIY but for sure it has to rate as one of the most frustrating things to happen. I am talking of dropping something you are using. Ranking high is dropping tools while you are actually using them..  Dropping a tool is one thing but imagine dropping an entire bag of tools, while in orbit!!!! Oops!

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Searching for the Supernova Neutrino Background to the Universe

Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526.
Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526.

It’s a sobering statement that stars like the Sun, more accurately ALL stars will die eventually, yes even the Sun! Don’t panic though, we still have a good few billion years to go so you will get to the end of this article. The more massive stars die as the dramatic supernovae explosions and when they do, they send a burst of neutrinos across the Universe.  Astronomers now think it’s likely there is a background of neutrinos across the cosmos and that one day we will be able to map the historical distribution of supernova explosions, may be even by 2035.

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Can There Be Double Gravitational Lenses?

The narrow galaxy elegantly curving around its spherical companion in this image is a fantastic example of a truly strange and very rare phenomenon. This image, taken with the NASA/ESA Hubble Space Telescope, depicts GAL-CLUS-022058s, located in the southern hemisphere constellation of Fornax (The Furnace). GAL-CLUS-022058s is the largest and one of the most complete Einstein rings ever discovered in our Universe. The object has been nicknamed by the Principal Investigator and his team who are studying this Einstein ring as the "Molten Ring", which alludes to its appearance and host constellation. First theorised to exist by Einstein in his general theory of relativity, this object’s unusual shape can be explained by a process called gravitational lensing, which causes light shining from far away to be bent and pulled by the gravity of an object between its source and the observer. In this case, the light from the background galaxy has been distorted into the curve we see by the gravity of the galaxy cluster sitting in front of it. The near exact alignment of the background galaxy with the central elliptical galaxy of the cluster, seen in the middle of this image, has warped and magnified the image of the background galaxy around itself into an almost perfect ring. The gravity from other galaxies in the cluster is soon to cause additional distortions. Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see.
Gravitational Lens GAL-CLUS-022058s taken with NASA/ESA Hubble Space Telescope

If you, like me, have used telescopes to gaze out at the wonders of the Universe, then you too may have been a little captivated by the topic of gravitational lensing.  Think about it: how cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time? 

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature’s own telescopes, but now part-time theoretical physicist Viktor T Toth poses the question, “Can there be multiple gravitational lenses lined up and can they provide a ‘communication bridge’ to allow civilisations to communicate?”

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The Crab Reveals Its Secrets To JWST

The NASA/ESA/CSA James Webb Space Telescope has gazed at the Crab Nebula in the search for answers about the supernova remnant’s origins. Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) have revealed new details in infrared light. Similar to the Hubble optical wavelength image released in 2005, with Webb the remnant appears to consist of a crisp, cage-like structure of fluffy red-orange filaments of gas that trace doubly ionised sulphur (sulphur III). Within the remnant’s interior, yellow-white and green fluffy ridges form large-scale loop-like structures, which represent areas where dust particles reside. The area is composed of translucent, milky material. This material is emitting synchrotron radiation, which is emitted across the electromagnetic spectrum but becomes particularly vibrant thanks to Webb’s sensitivity and spatial resolution. It is generated by particles accelerated to extremely high speeds as they wind around magnetic field lines. The synchrotron radiation can be traced throughout the majority of the Crab Nebula’s interior. Locate the wisps that follow a ripple-like pattern in the middle. In the centre of this ring-like structure is a bright white dot: a rapidly rotating neutron star. Further out from the core, follow the thin white ribbons of the radiation. The curvy wisps are closely grouped together, following different directions that mimic the structure of the pulsar’s magnetic field. Note how certain gas filaments are bluer in colour. These areas contain singly ionised iron (iron II). [Image description: An oval nebula with a complex structure against a black background. On the oval's exterior lie curtains of glowing red and orange fluffy material. Interior to this outer shell lie large-scale loops of mottled filaments of yellow-white and green, studded with clumps and knots. Translucent thin ribbons of smoky white lie within the remnant’s interior, brightest toward its centre.]
The Crab Nebula by JWST. Credit: NASA/ESA/JWST

The Crab Nebula – otherwise known as the first object on Charles Messier’s list of non-cometary objects or M1 for short – has never really failed to visually underwhelm me! I have spent countless hours hunting down this example of a supernova remnant and found myself wondering why I have bothered. Yet here I am, after decades of looking at it, and I still find it one of the most intriguing objects in the sky.

Never has this interest been piqued more than right now after another mirror-smashing beauty of an image from the James Webb Space Telescope, and it’s already found its way to my mobile phone wallpaper!

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In Case of Jerusalem Video, UFO Could Mean “Unidentified Flashlight Objects”

UFO’s are tricky little blighters. Those three letters have caused so much controversy over the years and I find myself, yet again, discussing one of the most misrepresented acronyms in the entire Universe. UFO stands for ‘Unidentified Flying Object’ and, if you have never seen a helicopter before, then its a UFO, its unidentified and flying! Forgive me then when I saw the news on January 28, 2011 of yet another UFO sighting and cries of alien visitors as if it were obvious. Well stop right there…..
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Planck Unveils the Wonders of the Universe

Six areas of the sky in which distant galaxies can be seen by Planck, overlaid on the Planck’s first all-sky image. The emission from our own Galaxy, seen in blue and white, has to be removed before the distant population of galaxies can be seen. Each square inset image is around the same size as the Full Moon. Image credit: ESA / Planck Collaboration.

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The mission began on 13th August 2009 with a goal to image the echo’s of the birth of the Universe, the cosmic background radiation. But scientists working on the European Space Agency’s (ESA) Planck mission got more than they bargained for making ground breaking discoveries and shedding light on old mysteries. By studying light from the far reaches of the Universe, Planck has to look through the rest of the Universe first and it was during this, that the incredible discoveries were made.

The crazy thing about looking at the far reaches of the Universe is that we actually look back in time as it takes billions of years for the light to reach us here on Earth. This enables astronomers to look back in time and study the evolution of the Universe almost back to the Big Bang itself. Amongst the discoveries was evidence for an otherwise invisible population of galaxies that seem to be shrouded in dust billions of years in the past. Star formation rates in these galaxies seem to be happening at an incredible pace, some 10-1000 times higher than we see in our own Milky Way galaxy today. Joanna Dunkley, of Oxford University, said “Planck’s measurements of these distant galaxies are shedding new light on when and where ancient stars formed in the early universe”.

One of the challenges of getting a clear view of these galaxies though has been removing the so called ‘anomalous microwave emission’ (AME) foreground haze. This annoying and poorly understood interference, which is thought to originate in our own Galaxy, has only just been pierced through with Planck’s instruments. But in doing so, clues to its nature have been unveiled. It seems that the AME is coming from dust grains in our Galaxy spinning several tens of billions of times per second, perhaps from collisions with incoming faster-moving atoms or from ultra-violet radiation. Planck was able to ‘remove’ the foreground microwave haze, leaving the distant galaxies in perfect view and the cosmic background radiation untouched.

Its also the ideal instrument to detect very cold matter in the form of dust in our Galaxy and beyond, thanks to its broad wavelength coverage. During its study, it detected over 900 clumps of cold dark dust clouds which are thought to represent the first stages of star birth. By studying a number of nearby galaxies within a few billion light years, the study shows that some of them contain much more cold dust than previously thought. Dr David Clements from Imperial College London says “Planck will help us to build a ladder connecting our Milky Way to the faint, distant galaxies and uncovering the evolution of dusty, star forming galaxies throughout cosmic history.”

These results make Planck a roaring success but it doesn’t stop there. Other results just published include data on galaxy clusters revealing them silhouetted against the cosmic microwave background. These clusters contain thousands of individual galaxies gravitational bound together into gigantic strings and loops.

The Planck mission, which was in development for 15 years is already providing some ground breaking science in its first few years of operation and its exciting to wonder what we will see from it in the years that lie ahead.

Mark Thompson is a writer and the astronomy presenter on the BBC One Show. See his website, The People’s Astronomer, and you can follow him on Twitter, @PeoplesAstro

Stars Shrouded in Glittering Zirconium Light up the Sky

Artist’s impression of LS IV – 14 116. The white clouds are rich in zirconium and lie above the blue surface of the star. Image: Natalie Behara

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Its been said that the Universe isn’t stranger than you can imagine, its stranger than you can’t imagine. Nowhere is this more true than the study of stars. Recently, a team of scientists from the Armagh Observatory in Northern Ireland have discovered a star that is enveloped by clouds of glittering zirconium! Its a metal you might be more familiar with in jewelry to make false diamonds but it now looks like stars are getting in on the act and becoming more sparkly than they are already.

The research team, led by graduate student N. Naslim and her supervisor Dr. Simon Jeffrey, were looking for clues to the lack of hydrogen on the surface of helium rich hot subdwarf stars, when compared to other similar stars. Using the 3.9m Anglo-Australian telescope at Siding Spring Observatory in New South Wales, the study focused on a star called LS IV-14 116 which lies at an incredible distance of 2000 light years.

By using a spectroscope attached to the telescope, the team was able to split the incoming starlight into its component parts (much like water droplets in the atmosphere do to sunlight to make a rainbow). Along with the expected patterns which showed the presence of certain elements, they were surprised to find lines in the spectrum which were not so easily identified. A careful study showed the lines were due to the presence of a form of zirconium that should only exist in temperatures in excess of 20,000 degrees. This was a first, no zirconium of this type had ever been found in a stellar spectrum before.

Team member Prof. Alan Hibbert built a computer model that enabled them to deduce that the zirconium existing on LS IV-14 116 was some ten thousand times more than the concentration found in the Sun. This highly unexpected result led the team to conclude that the abundance of zirconium is caused by the formation of cloud layers in the star’s atmosphere.

“The star doesn’t have a corona like the Sun. Our model shows the huge excess of zirconium that we discovered is on the photosphere (the visible ‘surface’ of the star), where it forms cloud layers much like stratus clouds on Earth.” Naslim told Universe Today. It seems that other elements, chiefly metals heavier than calcium, seem to form in high concentrations too but seem scarce in layers above and below. This could have a dramatic effect according to Dr. Natalie Behara from the Université Libre de Bruxelles appearing as many thin cloud layers in the atmosphere, each due to a different metal.

Further work from the team suggests that the star is shrinking from a bright cool giant to a faint hot subdwarf and as it does, different elements sink or float up in the atmosphere making the current composition very specific to the star’s recent history.

Naslim explains that “The huge excess of zirconium was a complete surprise. We had no reason to think this star was more peculiar than any other faint blue star discovered so far.” Its great to see that whilst we know so much about the Universe now, there are still discoveries that come along and surprise us. This latest discovery of zirconium rich stars has yet again shown us that we mustn’t become complacent and think we know everything, it keeps science interesting, it keeps it alive.

Source: from the Royal Astronomical Society.

Mark Thompson is a writer and the astronomy presenter on the BBC One Show. See his website, The People’s Astronomer, and you can follow him on Twitter, @PeoplesAstro