Seven Dwarfs, err, Planets

Summary: In a brand new press release from NASA, the agency has announced a discovery of seven Earth-sized planets, in the habitable-zone, around a single star. This is the largest star system with such properties and I am excited. The discovery was made by the Spitzer Space Telescope and follow up with ground based observatories.

To be fair, only three of these planets are definitely in the habitable zone, but with the right atmospheric conditions, all seven are likely to have liquid water. This exoplanet system has been called TRAPPIST-1 and the densities show that all planets are likely to be rocky planets like the inner planets of our own solar system. Unlike our sun, this star is an ultra-cool dwarf star that allows all of these planets to be closer to their star than Mercury is to our star. With all of these planets being so close, it is possible that an individual standing on the surface of one planet may be able to look up at the sky and see geological features on the neighboring planet without the aid of binoculars. We can barely do this with our own moon despite how close it is.

If you wanted to visit this system, it is relatively close to us, at only 40 light-years away in the constellation of Aquarius. But until we invent better spacecraft we can only take advantage of the nearness by turning more telescopes to the system. Hubble and Kepler are doing follow-up observations and, when it launches, the James Webb Space Telescope will collect further data.

NASA press release
360 VR of exoplanet surface
Nature

Artist's conception of the system based on known diameters, masses, and orbital distances, NASA JPL, Caltech

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

More Secret Oceans

Summary: Jupiter's moon Ganymede is the latest solar system body now thought to have a secret ocean lying beneath its icy crust. The evidence for this lies in the aurora produced by the moon's magnetosphere. The auroras are also influences by Jupiter, but not as much as scientists thought they should be. The presence of a salty ocean below the surface would counteract some if the effects of Jupiter and leave what we see now.

This new evidence means that we are past the point of ambiguity but not certain yet. We will know more when a probe in 2030 orbits the moon and finishes with a crash landing into the surface. 


BBC News

And Happy Pi Day!

New Record for Furthest Galaxy

Summary: Your friend in another country may seem incredibly far away, but this latest discovery will put that in perspective. A new record has been set for the most distant galaxy. The Hubble Space Telescope has found the galaxy z8_GND_5296 to be about 30 billion light years away. We are seeing this galaxy as it appeared just 700 million years after the Big Bang. To determine the distance, they looked at the redshift of the galaxy. It has a redshift of 7.51 which beats the previous winner of 7.21.

BBC News
Popular Science
Physics World

Cosmic Caterpillar

Summary: Hubble has yet another incredible space image for us. It is a cloud of gas that looks like a caterpillar. Unlike the small creatures we are used to on earth, this celestial caterpillar is 6 trillion miles long. It is actually a cloud of gas collapsing and may give birth to a star. But the important part is how beautiful it is.



Smithsonian Mag

Neptune's New Moon

Summary: US astronomer Mark Showalter has used pictures from Hubble to spot a new icy moon of Neptune. It was too tiny for Voyager to have picked up but with Hubble's higher resolution he was able to track the white blur across many years of images. It is Neptune's smallest moon measuring only 20 km (12 miles) across and completing one revolution around Neptune every 23 hours.


BBC News

New galaxies examined

Summary: The Hubble telescope has been used to look again in the area of the Hubble Deep Field and has found 7 new galaxies, one of which may be the most distant galaxy observed. We can tell by the redshift. (The further away a galaxy is, the faster it is moving away from us. Because it is moving so fast, the light gets shifted a measurable amount. Further away=greater redshift.)


SpaceTelescope.org: http://www.spacetelescope.org/news/heic1219/ (I know, a new source!)