Very close exoplanet

It turns out that the nearest exoplanet is right next door. Of course, the neighborhood is kind of on the large side. In this case, next door is 4.2 light years ago, orbiting Proxima Centauri, the closest star, not counting the sun. Proxima Centauri is a very small star, class M, and puts out very little light compared to what we’re used to. This planet (Proxima b) is orbiting in the habitable zone, the so-called goldilocks zone, where liquid water would be possible.

This makes it theoretically possible that life could evolve there. But this is unlikely since the amount of X-ray or Gamma-ray radiation from the star is about 100 of the amount we get, which would break down DNA very quickly. Any life would have to store genetic information in a very robust chemical. Because class M stars are so small, the habitable zone is also very small. Proxima b’s year is about 11.2 of our days long; it’s orbit would be well inside Mercury’s orbit.

Popular Mechanics has a good article on the planet.

Hypothetical 9th planet

Scientists claim that they have evidence for (but not observed) a new ninth planet of our solar system. This planet would be about the size of Neptune, and would orbit the sun about every 15,000 years. It’s closest approach to the sun (perihelion) would be about 200 AU out from the sun (200 times the distance from the Earth to the sun), while its furthest distance (aphelion) could be from 600 to 1200 AU.


New Horizons snaps pictures of Pluto’s small moons

New Horizons is due to get to Pluto in 59 days (closest approach on July 14). It has already taken photos of the small Plutonian moons. We’ve known about Pluto’s main moon Charon since 1978. The Pluto / Charon system is interesting because the barycenter of the two is outside the body of the primary. This means that the center of mass for Pluto and Charon is above the surface of Pluto.

The smaller moons were discovered in 2005 (Nix, Hydra), 2011 (Kerberos), and 2012 (Styx). They are orbiting Pluto over twice this distance of Charon. These are very small with the largest up to 172 km across.

Dark Matter not so dark after all?

We’ve never seen Dark Matter. But we know that there isn’t enough matter in galaxies to hold them together, so there must be something adding more gravity; that’s what we call dark matter. The problem is that the only effect it seems to have is gravitational. Light goes right through it. For all we know, matter can go right through it.

But it’s may not be quite so mysterious after all. Astronomers may have observed dark matter having an effect beyond just gravity. Researchers have been studying 4 galaxies colliding about 1.3 billion light years away. It seems that a dark matter clump is lagging behind its galaxy by about 5,000 light years. This is predicted if dark matter interacts with other forces. It seems the friction from the collision would slow the dark matter down.

Astronomers can see the dark matter clump because they are viewing the clump through a gravitational lens from galaxies between us and the galaxies being studied.

It’s official: Voyager 1 is in interstellar space

The Voyager 1 spacecraft, launched in 1977, is now traveling through interstellar space. But, oddly enough, is still in our solar system. Voyager 1 has left the heliosphere. This means that it has left the sun’s protective bubble, and is now moving through the thicker interstellar plasma. While far away from the orbits of the planets (and Pluto), it hasn’t reached the hypothetical Oort cloud, which would be the actual end of the solar system.

Laboratory supernova


Cassiopeia A supernova remnant

Supernovae come from stars many times our sun’s mass dying. The resulting explosion leaves behind supernova remnants that are very beautiful. But why aren’t they spherical? The remnant of Cassiopeia A certainly doesn’t look spherical.

Experiments in the UK using high powered lasers show that explosions that pass through a plastic grid create “knotty” results similar to the Cassiopeia remnant. This implies that the space the supernova exploded in isn’t uniform, there must have been some kind of turbulence there for the explosion to pass through.