GJ 357d is one of three planets found orbiting a tiny (300,000 miles diameter) M-type star 31 light years away. This so-called “Super-earth” is about 19 million miles out from the star, orbiting every 55 days, and is massive enough to have a thick atmosphere. It could be similar to Earth and potentially inhabitable. Further out (260 light years away) another planet has been detected that is 4.6 times Earth’s size and 29 times Earth’s mass (making it close in size to Neptune). It is 1.5 million miles from its star and orbits every 19 hours, about as close as a planet can get without being swallowed by its star. Its temperature checks in at 3,100 degrees Fahrenheit! Most other planets so close to their stars are either Earth-sized or Jupiter-sized, so this one is right in the middle of that range. It probably formed farther out, then migrated inward towards the star losing atmosphere as it heated or as the star drew the atmosphere off.

The universe is primarily comprised of so-called “dark matter.” We can’t see it, but we know it exists because we can see its gravitational effect. Some physicists think dark matter is made up of weakly interacting massive particles (WIMPs), but they have yet to be detected. Here’s another possibility; a very special quark-like particle that can travel unimpeded through the universe at hypersonic speeds. One group of scientists suggest that such a particle would bore a cylinder right through you but cauterize that path as it went because at those speeds, a one square micrometer (1,000 times smaller than a millimeter!) particle would generate about 18 million degrees of heat!

Sunrise now at 6:01am and sunset at 8:12pm, we’ve already lost 49 minutes of daylight. Jupiter and Saturn are night sky highlights, and a beautiful waxing crescent moon is visible after sunset now.