Only last month I recorded a DNews video about the awesome possibilities of the “Cold Spot” that sits ominously in the cosmic microwave background (CMB) anisotropy maps (anisotropies = teenie tiny temperature variations in the CMB).
I still hold onto the hope that this anomalous low temperature region is being caused by a neighboring parallel universe squishing up against our own. But evidence is mounting for there actually being a vast low density region — known as a “supervoid” — between us and that Cold Spot.
And that’s crappy news for my dreams of cosmologists finding bona fide observational clues of the multiverse hypothesis any time soon. The Cold Spot could just be the frigid fingerprint of this supervoid etched into our observations of the CMB.
But as this supervoid could be as wide as 1.8 billion light-years, this discovery is still crazy cool — the supervoid could be the newest candidate for the largest structure ever discovered in the universe. Suck it, Sloan Great Wall.
Read more about this new research published today in the Monthly Notices of the Royal Astronomical Society in my Discovery News blog.
A map of the faint microwave radiation left over after the big bang shows superclusters (red circles) and supervoids (blue circles). Credit: B. Granett, M. Neyrinck, I. Szapudi
A new cosmic map has been created by University of Hawaii astronomers showing the fingerprint of dark energy throughout the observable Universe. This is the first time such precise direct evidence of the mysterious force that is believed to be behind the continuing expansion of the Universe. By analysing microwave background radiation (the electromagnetic “echo” left over from the Big Bang), the Hawaii team have looked at the characteristics of the radiation as it passes through supervoids and superclusters. If the theory of dark energy is correct, this cosmic background radiation should cool when passing through superclusters and warm up when passing through supervoids. Analysing a huge amount of data from the Sloan Digital Sky Survey, the researchers have observed what the theory predicts and calculated that there is a 1 in 20,000 chance that their results are random. It therefore seems likely that the effect is caused by the presence of dark energy, giving us the best view yet of this strange energy that appears to permeate through the entire expanding Universe…
Chandra observation of Cassiopeia A, a young supernova remnant in our galaxy - a prominant source of high-energy particles (NASA/CXC/MIT/UMass Amherst/M. D. Stage et al.)
There is something strange happening in the core of the Milky Way. A space observatory measuring the energy and distribution of gamma-rays in the cosmos has made an unexpected (and perplexing) discovery. It would seem there is a very high proportion of gamma-ray photons emanating from our galactic core with a very distinctive signature; they have a precise energy of 511 keV (8×10-14 Joules), and there’s a lot of them. So what could possibly be producing these 511 keV gamma-rays? It turns out, 511 keV is a magic number; it is the exact rest mass energy of a positron (the antimatter particle of the electron). So this is fairly conclusive evidence that positrons are dying (i.e. annihilating) in vast numbers in our galactic nuclei. Still, this is of little help to astrophysicists as there is no known mechanism for producing such high numbers of annihilating positrons. Ideas have been put forward, but there’s a new possibility, involving some new particle physics and some lateral thinking…
There is a trend in astronomical observations to label strange and exotic objects with superlative names. Take “supermassive” black holes for instance. Yes they are more massive than intermediate black holes, bigger than stellar black holes, and in a whole different league to theoretical micro-black holes. But is the label “supermassive” an accurate description? Is it even scientific?
After reading a very interesting article written by Michael Gmirkin on “Incorrect Assumptions in Astrophysics“, I began to relate his investigation into the use of terms to describe astronomical phenomena with very expressive names. Terms like “super-massive”, “ultra-luminous”, and “beyond-bright” are mentioned by Gmirkin, perhaps leading astronomers to incorrect conclusions. Whilst this may be perceived as an issue amongst scientists, what if the media or non-specialist individuals misinterpret the meaning of these grand statements? Could it lead to public misunderstanding of the science, possibly even causing worry when a scientist describes a particle accelerator collision as “recreating the conditions of the Big Bang”?
So what does happen? Will the stars crash into one another, sending out huge emissions of gamma radiation and gravitational waves? The effects of two galaxies meeting and colliding are actually a little more elegant than that – for starters, it’s most likely that none of the stars will meet due to the huge distances between star systems. Also, the merging of the systems will spark a huge campaign of star creation within the newly formed fertile gas clouds. So what will we see long after the galaxies have ripped each other apart? Simulations show huge arcs of tidally-formed dust and stars, looking strangely like the precursors to the galactic ghosts recently observed…
It’s been a busy day with a range of topics posted on the Universe Today, but all have a common thread: the universe is a deadly place for man and galaxy. For starters, research into the radiation mankind will face when settling on Mars and the Moon could prove to be one of our main challenges in space. The threat of a massive dose of radiation from a solar flare is bad enough, but the gradual damage to our cells and increased risk of cancer is a problem we need to solve, or at least manage. But that’s nothing compared with what dwarf galaxies have to put up with; their larger spiral cousins like to eat them for dinner, leaving behind galactic ghosts of the dwarfs that were…
This week has been an exciting week for astronomers. The largest explosion ever seen in the Universe was observed on Wednesday. This gamma ray burst, produced when a star collapses in on itself to create a black hole, is a record breaker. Not only is it the biggest explosion mankind has seen since records began, it is also the furthest and oldest “thing” we have ever observed…