EarthSky

The NEAR Shoemaker spacecraft captured this movie of Eros on December 3-4, 2000, while in orbit 125 miles (200 km) from the center of this asteroid. Image Credit: NASA / Johns Hopkins University Applied Physics Laboratory

Hello asteroid 433 Eros … and goodbye. We got a slightly panic-y sounding comment from a Facebook friend yesterday about asteroid 433 Eros, which will be making its closest approach to Earth since 1975 today (January 31, 2012). Afterwards, I saw a few misleading headlines about this event. Yes, Eros is passing closer on Tuesday than it has in some decades. In fact, although I had a tough time finding the information, its perigee – or closest point to Earth – appears to be January 31 at around 11 UTC – or 5 a.m. CST – which means it has already passed closest. The closest point of Eros was not very close. At its closest, it was about 16,608,000 miles (26,729,000 km) away – some 70 times the moon’s average distance. It was some 80 times farther than the closest point of a much smaller body that passed safely within the moon’s orbit on November 8, 2011. That object was called 2005 YU55. So there was – and is – absolutely no danger at all from 433 Eros at this 2012 passage.

Here is a list of 10 interesting facts about stars. For example, here is number five:

5) The Sun is a green star
The Sun is a “green” star, or more specifically, a green-blue star, whose peak wavelength lies clearly in the area on the spectrum between blue and green. This is not just an idle fact, but is important because the temperature of a star is related to the color of its most predominate wavelength of emission. (Whew!) In the Sun’s case, the surface temperature is about 5800 K, or 500 nanometers, a green-blue. However, when the human eye factors in the other colors around it, the Sun’s apparent color comes out a white or even a yellowish white.