At 9:24am GMT on 31 October 2016, near-Earth asteroid 164121 (2003 YT1) will safely fly by at a distance of 3.2 million miles (5.2 million kilometres), or 13.5 times the distance of the Moon. Furthermore, this 1.1-mile-(1.7-kilometre)-wide Apollo asteroid also passes very close to Polaris early on 2 November, creating a rare astrophotographic and observing opportunity.
Have you ever seen Mercury with the naked eye? If not, now is the time to check the elusive innermost planet off your list. Mercury reaches greatest easterly elongation from the Sun on Monday, 18 April, the highlight of a very favourable dusk apparition in the west-northwest for observers in Western Europe and the British Isles.
A scholarly investigation of the Cairo Calendar papyrus (1244–1163 B.C.) has led researchers at the University of Helsinki to conclude that the ancient Egyptians were aware that the variable star Algol (beta Persei) had a 2.85-day period. Given that the star’s current period is 2.8673 days, this supports the theory that mass transfer between the stars of this eclipsing binary has caused a long-term increase of its orbital period.