A plutino is an asteroid-sized body that orbits the Sun in a 2:3 resonance with Neptune. They are named after Pluto, which also orbits the Sun twice for every three orbits of Neptune. It is thought that Pluto and the other plutinos were clustered into this resonance during the migration of the outer planets during the early solar system.
Dust in the Wind
With all the news about Voyager 1 leaving the heliosphere and entering interstellar space you might think that the probe is the first spacecraft to detect interstellar particles. That isn’t entirely true, and the latest observations of interstellar particles has found some very interesting results.
Elvis Has Left the Building
Last year Voyager 1 has left our solar system. Kind of, depending on how you look at it. There were lots of stories in the news about how NASA officially announced that Voyager 1 has left our solar system, but the actual announcement was that the probe has crossed what is known as the heliopause.
Ancient Rings
Saturn is everyone’s favorite ringed planet. It’s ring system is both complex and extraordinarily bright. Just why it is so bright has been a bit of a mystery. It’s brightness is due to the fact that the rings are composed almost entirely of water ice, and the fact that there isn’t a great deal of dust in the rings. Because of this, it was once thought that Saturn’s rings were generally young. If the ring system were old, one would expect it to darken over time as dust and other debris from the solar system accumulate over time. This also agreed with the idea that such a complex ring system would likely be unstable over millions of years.
Blood Ore
Hematite is a fairly common iron oxide mineral. The particular sample seen above comes from the iron range of northern Minnesota. It is about 2.7 billion years old, and is a type of hematite known as gray hematite. It doesn’t look very gray in the picture, since it has been exposed to air and water since its formation. Typically when you see hematite, it is carved and polished so that it looks like gray metallic stone, but in its raw form its surface is usually reddish in color, which is why it is also known as “blood ore.
Mars Transit
About a year ago Curiosity happened to be in the path of an eclipse. So Curiosity was directed to take a series of photographs of the Sun. You can see the result here. The shadow moving across the Sun is Phobos, and you can see it pass in real time. Phobos is must smaller than our Moon, only about 27 …
Snow White, Rose Red
Beyond Neptune, and just slightly closer to the Sun than Eris, is a solar system body designated as 2007 OR10. With a diameter of about 1200 km, it is the largest solar system body without an official name, but it has been given the nickname Snow White. Snow White is one of the reddest objects in the solar system, likely due to methane …
The Planet That Never Was
While there were speculations about a planet closer than Mercury going back to at least the 1600s, it wasn’t until the 1850s that Urbain Le Verrier discovered the first indirect evidence for such a planet. Le Verrier carefully calculated the orbit of Mercury, and determined that the orientation of its orbit rotated slowly over time. This is known as a perihelion advance, and it is due to the small gravitational pulls from other planets.
Newer Horizons
The New Horizons spacecraft is on its way to Pluto. It will fly-by the dwarf planet in July 2015. The spacecraft will have far too much speed to stay near Pluto, so after its visit the craft will continue its journey away from the Sun. Given that Pluto marks the inner edge of the Kuiper belt, it would be nice if New Horizons could explore other Kuiper belt objects.