An impossible star? No, it just means that we don’t know everything yet.

So stars are born, they live, and they die. Large stars die in a supernova. And that’s it.

Except that it isn’t. Scientists have found a star that has had multiple supernovas. One in 1954, the other in 1993. This is impossible given our current understanding of how stars work. Which means that we need to change our understanding. Our current theories are wrong and need to be changed. This is the exciting part of science, when our understanding has to change to fit the facts.

… it wasn’t willing

So my son and I go to St. Joseph, MO to see the eclipse. And the clouds roll in. And it rains a bit. We get to see some of the partial before totality, but only get to see 4 seconds of totality. This is the pic I took with my phone:

The best photo I’ve seen from St. Joseph was this one.

Hope you saw a better eclipse than we did. Even so, experiment_1 said that it was worth it.

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.