Centauri Dreams 22 Oct 2018, 16:37 UTC We have somewhere between 200 billion and 300 billion stars in our galaxy (the number is flexible enough that you’ll see a wide range in the literature). Relate that to the Local Group, the gathering of galaxies that includes both the Milky Way and M31, the Andromeda Galaxy. These are the two most massive members of the Local Group, but depending on how we count dwarf galaxies, it contains more than 30 members spread out over a diameter of 10 million light years. Both the Milky Way and M31 have their own dwarf galaxies. Then consider the concept of a ‘supercluster,’ which contains galaxy groups within it. Thus the Milky Way is considered part of both the Local Group as well as the Laniakea Supercluster, which is itself home to approximately 100,000 galaxies and subsumes the Virgo Supercluster. The Laniakea Supercluster emerged in the literature in 2014 in a paper examining the relative velocity of galaxies. Laniakea is a Hawaiian word meaning ‘immense heaven.’ R. Brent Tully (University of Hawaii at Manoa) and team identified this structure some 520 million light years in diameter, containing 100,000 galaxies, with a mass of one hundred million billion Suns.
Astro Watch 21 Oct 2018, 19:19 UTC A house-sized asteroid detected just few days ago, designated 2018 UH1, will pass by the Earth on Wednesday, October 24, at around 5:00 UTC. The space rock is expected to fly by our planet with a relative velocity of about 13 km/s at a safe distance of approximately 5.3 lunar distances (LD), or 2.03 million kilometers.
EarthSky Blog 20 Oct 2018, 18:00 UTC Penitentes – large pointed spikes of ice – are known on Earth and Pluto. Jupiter’s moon Europa might have them, too, according to new research. If they’re there, they could make a future landing on Europa tricky.
David Reneke's World of Space and Astronomy 20 Oct 2018, 09:41 UTC Popular science fiction of the early 20th century depicted Venus as some kind of wonderland of pleasantly warm temperatures, forests, swamps and even dinosaurs. Another earth in fact.
NPR 19 Oct 2018, 18:57 UTC The European Space Agency is sending a mission to explore the mysteries of Mercury.BepiColombo, named after the Italian mathematician and engineer Giuseppe "Bepi" Colombo, launched at 9:45 p.m. ET Friday aboard an Ariane 5 rocket from a spaceport in French Guiana.