Tag: astronomy

99.99% dark matter Galaxy

Dragonfly 44 is a dim galaxy, with 1 star for every 100 in our Milky Way. But it spans roughly as much space as the Milky Way. In addition, it’s heavy enough to rival our own galaxy in mass. That odd combination is crucial: Dragonfly 44 is so dark, so fluffy, and so heavy that some astronomers believe it will either force a revision of our theories of galaxy formation or help us understand the properties of dark matter, the mysterious stuff that interacts with normal matter via gravity and not much else. Or both.

Kardashev Type II beacon?

If that beacon is transmitting radio waves in all directions, the energy it would need to produce is a whopping 10^20 watts. “That’s a big energy bill even if you’re getting a bulk discount from your local supplier. It’s 100s of times more than all the energy falling on the Earth from sunlight.”

That means the hypothetical beings responsible might be what SETI scientists call a Kardashev Type II civilization, so advanced that they can tap all of the energy being produced by their host star.

Niku TNO

Astronomers have recently discovered a new mystery object orbiting the sun on a plane nearly perpendicular to the rest of the planets. Adding to the weirdness, the trans-Neptunian object, which has been nicknamed “Niku,” is also spinning around the sun backwards, in the opposite direction of the rest of the planets. So far, astronomers have little idea what could cause such abnormal celestial behavior.

100B Galaxies

Just by taking this observation and applying some high school math, we have discovered that the Universe has something like a 100B galaxies in it. And each of those galaxies has billions of stars. There are something like a sextillion stars in the Universe. And it’s reasonable to think that most of those stars have planets, perhaps multiple planets. How many are Earth-like? How many have life?

Super-Earth in our solar system?

It doesn’t seem to be part of the Proxima Centauri system, it must be closer and correspondingly smaller. With just 2 observations it isn’t possible to determine the object’s orbit, so we can only guess at its distance and size. One possibility (and the one I think most likely) is that it’s an extreme trans-Neptunian object ~100 astronomical units away from the Sun, which is further than Sedna at 86 AU. This would make it the most distant known object in the solar system, but likely smaller than Pluto.

Another possibility (which seems more likely to the object’s discoverers) is that it is ~300 AU away and ~1.5 times the size of Earth, making it the first “super-Earth” found in our solar system. Observations of trans-Neptunian objects have led to some speculation that 1 or 2 super-Earths could lurk in the outer solar system, so it’s not out of the question. There’s reason to be cautious of this idea, however, because of its location. Proxima Centauri is ~42 degrees away from the ecliptic. Most large solar system lay within a few degrees of the ecliptic, and even Sedna’s orbit is only inclined ~12 degrees from it.

A third possibility is that the object is a cool brown dwarf ~20k AU away. Such an object should also be visible in the infrared, so there would still be the question as to why it wasn’t discovered by earlier infrared sky surveys. Its proximity to Proxima Centauri would seem to make such an object easy to find.