Blue Skies A 100 Lightyears Away

Why is the sky blue? Light and other electromagnetic waves can interact with particles smaller than the wave itself creating a phenomenon called Rayleigh scattering. Light waves travelling from the sun to the earth interact with particles in the atmosphere to create diffuse sky radiation giving the sky its blue color and the sun a yellow hue. Nearby, only 100 light years away, the exoplanet GJ 3470b shows blue skies, signs of Rayleigh scattering. Astronomers know that GJ 3470b is a transiting in front of a nearby star, enough to change the amount of light we receive from that star. After taking a spectrum of the wavelengths created by the light traveling through the atmosphere of this planet researchers were able to determine what the atmosphere looked like in terms of color and opacity. From this they were able to determine that the atmosphere surrounding the planet was a blue color. This is significant for a couple main reasons, one being that this planet is the smallest exoplanet for which a blue, complete atmosphere is found, about 4 times the size of Earth. This is exciting because there is now reason to believe there is a hydrogen rich atmosphere. 
 
More information can be found at phys.org | dailymail.co.uk

New Distance Measurement Methods Using Quasars

As the new era of physicists, we are continuously looking for new ways to collect data from our universe. Unfortunately collecting data at large distances is somewhat of a challenge considering there is a vast amount of time and space that cosmological information has to travel through for us to collect any sort of relations from it. In class we studied how a nearby star's distance could be gauged by observing it's movement as the Earth orbits around the sun. 

We call this the parallax and it can be very useful, but for distances much larger than our galactic neighborhood the parallax is nearly nonexistent. For some time now, astronomers have used type 1a supernovae to calculate distances from Earth out into the universe. A type 1a supernova's luminosity can be calculated very precisely, enough for astronomers to be able to find the distance through its apparent luminosity. While these supernova are bright enough for us to see and calculate distances further than our galaxy there is still an infinite distance that we cannot completely gather information from.

Researchers have now found a new way to measure distances using ultraviolet and X-rays that are a produce of quasars found further than the type 1a supernovae that have been used for distance measurements in recent decades. The information that these ~1,138 quasars provide are in agreement with the data collected from the supernovae, with a little more error. These quasars give a better look at the early development of the universe and how the mass and energy has been distributed in the 13 billion years it has existed. Dark matter and dark energy are also measured through the rays emitted by the quasars. Other information provided by collecting quasar data is correlated to the expansion history of the universe. Perhaps from more information like this we can pinpoint when and where the time and the universe began.

More information can be found at hubblesite.org | phys.org