101 must-see cosmic objects: M87

M87 is another elliptical Messier galaxy in the Virgo cluster, 55 million light-years distant and some 120,000 light-years wide. It lies about 3½° northwest of Rho Virginis. But M87 surpasses M84 and M86 in terms of mass: it has at least…

Astronomy & Astrophysics 101: Comet

This ground image of Comet C/2020 F3 (NEOWISE) was taken on July 16, 2020 from the Northern Hemisphere. The inset image, taken on August 8, 2020, by the Hubble Space Telescope, reveals a close-up of the comet after passing through the Sun.…

101 must-see cosmic objects: M104

Dust is a common component of spiral galaxies. Astronomers believe this dust is carbon- or silicate-rich and no more than 0.25 microns wide. This does not greatly affect the brightness of galaxies, except in cases where they appear almost…