Before the application of the telescope to astronomy in 1608, the human eye was the only observing instrument available.
So what does this subject have to do with astronomy?
The Constellations we are familiar with are the “official” Greco-Roman ones accepted by the International Astronomical Union.
Mercury is only 0.38 the size of Earth and one of only two planets nearer to the Sun than us, the other being Venus, and therefore is never seen in the evening sky.
In the common vernacular the term theory is often used to mean a hunch, supposition, guess or speculation.
WILLIAMS, Ariz. — Since ancient times, people have observed the skies, but only in the visible spectrum (red-orange-yellow-green-blue-violet) and with only their unaided eyes.
Although there are about 30 annual meteor showers, only a few are often spectacular, such as the November Leonids, the December Geminids or the August Perseid show, which often exhibits many “shooting stars” and has a maximum intensity falling around Aug. 12.
On April 10, scientists revealed for the first time an image taken of a super-massive black hole.