One of the brightest galaxies in planet Earth's sky and similar in size to the Milky Way, big, beautiful spiral M81 lies 11.8 million light-years away in the northern constellation Ursa Major. This...

In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with Alpha and Beta Centauri on modern star charts. The new star was visible to the naked-eye for months, and is now thought to be the earliest recorded supernova.

Why might you want to visit super-earth Cancri 55 e? Its extremely hot climate would be a deterrent, as mornings on this world might bring fresh lava flows. Discovered in 2004, the planet Cancri 55 e has twice the diameter of our Earth and about 10 times Earth's mass.