Gaia and a new Age of Universe

Summary: The study of astronomy is an old one, but as headlines show, it is a constantly changing field. As our instruments change, we discover that the numbers we thought we knew need some readjustment. In this case, the Gaia space craft from the esa is forcing astronomers to look about the expansion rate of the universe. Again.

This is not the first time there have been some discrepancies in the estimate for the age of the universe. But Gaia is one of the most precise telescopes we have at the moment. Just recently it published precise coordinated for one billion stars. This is leaps ahead of the last survey of this type.

Gaia's estimate of the age of the universe is based upon Cepheid variable stars. These stars pulse with a very specific brightness and rate of pulsation. This makes it easier to tell how far away they are from us and to determine the age of the stars nearby. Gaia has precisely found 212 of these Cepheid stars and with these data, Professor Reiss's team calculates a Hubble constant of 73km/Mpc. This is about the same as they calculated with Hubble data. But it is not the same number found in most textbooks as the accepted value. And it is not due to outdated textbooks. It is because of the methods used to solve for the Hubble constant. The Planck mission gives a much lower value of 66.9km/Mpc.

Why is there such a discrepancy? We aren't entirely sure, but we can probably place a lot of the blame on dark matter. Hopefully as Gaia continues forward on it's mission, we will be able to narrow down the range of possible Hubble constants, and thus the age of the universe and no longer have a few hundred million year gap. Maybe we will even be able to place stricter bounds on what dark matter actually is and what effect it has on our universe.

Source

Also, the Ig Nobel prizes were awarded this week and they are, as always, amazing.

Expanding Expansion

Summary: Based on new data from the Hubble Space Telescope, the universe might actually be expanding faster than previously thought. This new data comes from an updated study of the velocities of Cepheid Variable Stars and Type Ia Supernovae to determine a value for the Hubble constant. The new data points to a slightly higher value of 73.24 km/sec/Mpc. This is only slightly higher than the value of 70 used in many textbooks.

However, this only increases the gap between the value gained from this method and the value gained from the Planck telescope. Those experiments lead to a Hubble value of 66.53 km/sec/Mpc. This means the difference of a few hundred million years when calculating the age of the universe.

At this point, astronomers can only guess at the cause of the discrepancy. Many point fingers at Dark Energy or a fourth flavor of Neutrino, but ultimately we hope that the next generation of telescopes can show us the answers.

Source:
BBC News
arXiv

A Shattering of Old Dark Matter Theories

Summary: Thanks to new data, further theories of the nature of dark matter have been smashed to pieces! Pardon me for being excited about leading theories being wrong but that only means that I may have a part to play in developing the correct theory. So what has changed?

It turns out dark matter really doesn't seem to interact with anything apart from gravity. It doesn't even interact with itself. The study was conducted my using the Hubble and Chandra to look at collisions of different galaxies and watch the dark matter. Well, it looked at the gravitational lensing since dark matter itself is essentially impossible to see.

In the way science should work, Dr. Massey explains that "if you want to figure out what something is made out of, you knock it, or you throw it across the room and see where the bits go." The surprising part was that unlike the stars that slide past each other and the gas clouds that come to a halt in these collisions, the dark matter "seems not to interact with anything at all." Rather like a ghost, it just glides through the other dark matter like it's no big deal. Since it doesn't even interact with itself, many prominent theories for what dark matter is has now fallen apart. Which means exciting new possibilities for the rest of us in the future. 


BBC News
Science Mag

Smorgasbord of Articles

I have not had much time of late to write up, or even read some of these articles and while I hope to catch up over my break, I do not wish to deprive you of them any longer than necessary. So here are a bunch of potentially interesting articles.

Quantum 'world record' smashed
New invisibility cloak type designed
Physics probes 'splashback' problem
Freak space rock spins dusty trail
India Mars probe makes first burn
Olympic torch in first spacewalk
Laser ripping apart spacetime to create ghosts
New Super-Black Material
Superconducting video camera seeing in living color

Source for Dark Matter and Antimatter News

I stumbled upon a link on the APS website to an archive of all their cosmology news which includes lots of articles on Dark Matter and antimatter and the beginnings of the universe. If any of that interests you, don't hesitate to check it out.


APS-Cosmology

Another Disappointment in Dark Science

Summary: One possible explanation for all of this Dark Matter that should be detected but isn't, is that Dark Matter could consist of relatively small black holes created in the early days of the universe. However, lack of data from Kepler supporting this theory has crossed of another possibility on our 'What in Sagan's Name is this stuff?' list.



American Physical Society

Dark Matter article

This month's (May) Discover magazine has a fantastic article on the history of Dark Matter, what we know know, and what is planned in the future. It's a great read for anyone who is interested.

Curiosity and other updates

Summary: Curiosity has discovered that most of Mars's atmosphere has since departed into space. Scientists discovered this by looking at the chemical of argon. Argon reacts with very little so the only way the lighter isotopes will have given way to a majority of the heavier isotopes is by escaping into outer space. The article does not comment on what this means when trying to determine whether or not Mars ever had flowing water other than to say that scientists are still split.


BBC News: http://www.bbc.co.uk/news/science-environment-22063337


Summary: The Alpha Magnetic Spectrometer (AMS) in the sky has made some observations that may give additional evidence to dark matter. Stay tuned.

BBC News: http://www.bbc.co.uk/news/science-environment-22016504


Summary: The LHC is being upgraded so that is can find new particles. Not too much info at this moment.


BBC News: http://www.bbc.co.uk/news/science-environment-21941666

Closing in on Dark Matter

Too exciting not to share before I write a summary though one will be coming.



** Dark matter hints 'to be chased' **
The team behind the Fermi telescope opens a call for changes to how it works - in a bid that could see hints of the mysterious "dark matter" confirmed.
< http://www.bbc.co.uk/news/science-environment-21043381 >


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-Jennifer

Dark matter

If you do not understand Dark Matter, here is a good blog post comparing the universe to making a cake.

Scienceblogs: http://scienceblogs.com/startswithabang/2012/12/07/yes-we-really-really-need-dark-matter/#.UMoxBFcfs8I.twitter

Dark Matter going Underground

Summary: A Dark Matter detecting experiment will be moving underground from it's current location at Fermilab in Chicago.

SymmetryMag: http://www.symmetrymagazine.org/breaking/?p=16324

Dark matter tracks could give earliest view of Universe

Summary: It seems as though scientists have come up with a new way of studying dark matter based on wavelengths. I can't say I fully understood it though.

BBC News: http://www.bbc.co.uk/news/science-environment-18521713

Telescope to probe dark universe

Summary: Europe is set to launch a telescope to investigate dark energy and dark matter in the year 2019. The US will have a very small role but some American scientists will be allowed access to the data. 

BBC News: http://www.bbc.co.uk/news/science-environment-18503703

Majorana particle

Summary: A particle that is the opposite of itself (it does not have an antimatter equivalent) was theorized by the crazy scientist Ettore Majorana. After 75 years it seems as if Dutch scientists may have found this mysterious particle that could hold a key to learning more about dark matter.


BBC News:http://www.bbc.co.uk/news/science-environment-17695944


SciShow: http://youtu.be/rOztrDmFFWM
(The above video also includes info on the possible discovery of life on Mars)

Dark matter theory "may be wrong"

BBC News Story:
http://www.bbc.co.uk/news/science-environment-14948730

Summary: Scientists have been looking at the formation of dwarf galaxies and have noticed the formation does not match up exactly with their computer models. They realized this may mean their understanding of dark matter may be slightly off.

Dark matter hunters see 67 hints

BBC News story:
http://www.bbc.co.uk/news/science-environment-14811580

There is more solid proof of Dark Matter!