Herschel records three moons for Georgium Sidus (Uranus), while today as many as 27 are recognised. Many of these, however, are mis-shapen lumps of rock. Also on this copper engraving are 26 figures ...

Moons of Uranus surprise scientists in Hubble study by Space Telescope Science Institute edited by Stephanie Baum, reviewed by Robert Egan Editors' notes ...

Astronomers used the Hubble Space Telescope to image "peculiar" galaxy Arp 184 (NGC 1961) about 190 million light-years away. Remarkably, the spiral galaxy has only one visible arm.

A view of the spiral galaxy NGC 3982, as seen by NASA’s Hubble Space Telescope. Galaxies come in many different variations, but astronomers classify them into four main types: spiral, elliptical ...

Galaxy Arp 184, however, we are seeing from an angle, so it looks different. More than that, though, Arp 184 is skewed so that it isn’t perfectly spiral shaped.

The upshot is that we now know that a day on Uranus takes 17 hours, 14 minutes, and 52 seconds, or 28 seconds longer than the best previous estimate made by NASA’s Voyager 2 during its 1986 flyby.

Like the sun’s other giant worlds, Uranus (seen in this 1986 photo from the Voyager 2 spacecraft) radiates more energy than the sun gives it, though not nearly as strongly as its massive peers do.

The galaxy NGC 5084 has been known for centuries. It was first cataloged by William Herschel in 1785, and has been well studied since. It's what is known as a lenticular galaxy – one that's somewhere ...

There are also elliptical galaxies, which are large and spherical rather than flat, similar to a rugby ball. The latter don’t produce new stars but are dominated by stars formed more than 10 ...

Galaxies are broadly divided into three groups. You have the spirals like the Milky Way and Andromeda, the irregular galaxies, and the elliptical galaxies. This latter group tends to have the most ...