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# Show Notes

### Evidence for Cosmic Inflation

On Monday, March 17, 2014, the group from BICEP2 told the world they think they have found evidence for cosmic inflation, which occurred in the earliest infancy of the Universe.
What is Inflation? Cosmic Inflation was an idea proposed by Alan Guth (with work done by many others) in 1980, designed to fix some long standing problems in cosmology (horizon, flatness, missing magnetic monopole..and others). In order to solve these problems, Guth proposed that the Universe underwent an exponential expansion (at velocities much faster than the speed of light) in a very short time frame. According to the theory, inflation occurred when the Universe was 0.000000000000000000000000000000000001s old ($10^{-36}$s), and lasted about 0.000000000000000000000000000000001s ($10^{-32}$s). In that (what would seem) very short time, the Universe became many orders of magnitude bigger (some models showing as much as $10^{50}$x bigger!). The problem, however, is there was no direct evidence of this expansion (only indirect…solving the issues above). The BICEP2 group has now found direct evidence of inflation by measuring the polarity of light left over from the big bang (in the Cosmic Microwave Background). If inflation is true, then it’s mark should have been left on the CMB in the form of gravitational waves (predicted by Einstein’s GR, which is celebrating a birthday today!). After meticulous working of the data, the BICEP2 group is claiming to have found gravitational waves to a statistically significant value (5$\sigma$, or to roughly 1 in 2 million chance of being wrong).

### Waves on Titan

The Cassini Spacecraft currently orbiting Saturn has made some interesting observations of the methane and ethane lakes on the surface of the moon Titan. On Punga Mare, one of Titan’s lakes, Cassini measured solar glint, which is reflection from the Sun off the lakes. This is pretty normal. The researched also noticed that a few of the pixels seem to be brighter than normal, indicating they Sunlight is glinting off something ‘choppy’ or uneven. This would indicate there are waves in the lakes of hydrocarbon’s on Titan. Saturn’s biggest moon, Titan is the only other object in the solar system to have surface liquids, however, they have been observed to be very still. This could be due to either, 1) the lakes are very viscous, making it hard to build up a wave pattern, or 2) the wind in the air isn’t strong enough to push it. These waves, if confirmed they are, would only be a few centimeters high, but they are telling of oceanography on the moon. Researchers think that as Titan moves out of winter into summer, the extra heat will drive bigger waves, and perhaps may be easier to find.
More Reading: Nature News, io9 article

### Hubble observes asteroid breakup

The Hubble Space Telescope has observed what appears to be an asteroid spontaneously breaking up. It was first found in an all-sky survey as a fuzzy patch, which was then targeted for follow up observations by Hubble. As Hubble took multiple images, it was clear that a solid chunk of asteroid had fallen apart into as much as 10 smaller fragments. Note this is located in the asteroid belt about 2.5x further away from the Sun than the Earth.

Hubble is showing the fragments drifted away at a slow 1.5 kilometers per hour. The likely scenario is that the asteroid was spun up by the effects of Sunlight (and re-radiating). The rotation made the asteroid spin fast enough to overcome it’s own internal binding structure, leading to it tearing apart. This indicates the asteroid was less a solid rock, and more the well known ‘rubble pile:’ a loose conglomerate of smaller pieces held together by mutual gravity.