Other than the Moon and fleeting objects like bright meteors and artificial satellites, the planet Venus is the brightest body in our night sky. It far outshines all the stars and other planets. And Mercury, although most have never seen it, also gets brighter than any star.
But as bright as they are, these two innermost planets orbit nearer the Sun than does Earth and thus are seen only in the morning or evening, never in the middle of night. When blazing in the morning sky, Venus is called the “morning star,” and when in the evening, the “evening star.”
At the moment, neither Venus nor Mercury is readily visible as both are hidden in the glare of the Sun.
Venus spends some eight months as the “morning star” before hiding from view for some six weeks while passing behind the Sun (a position called superior conjunction). It then becomes the “evening star” for eight months before again hiding from view for another six weeks when it passes between the Earth and Sun (called inferior conjunction).
This 584-day cycle, repeated year after year, was well known to several ancient civilizations, like the Mayas of Central America for whom Venus was an important god.
This year Venus passes directly behind the Sun June 8. It then begins its stint as the “evening star” in early July, and remains in the evening sky the rest of 2008.
Mercury follows a similar but more rapid pattern with a 116-day cycle. Being nearest the Sun, Mercury speeds around our star faster than any other planet, zipping along at 107,000 mph and completing its orbit in a mere 88 Earth-days. (For comparison, Venus travels 78,000 mph, orbiting the Sun every 225 Earth-days, and Earth, traveling 67,000 mph, orbits the Sun every 365 days.)
Owing to its more elliptical and tilted orbit, Mercury’s periods of visibility and invisibility are more varied. On average, it spends some six weeks in the morning sky, two weeks hidden in the glare of the Sun, six weeks in the evening sky and another two weeks in the Sun with the cycle being repeated about three times each Earth year.
June 7, the day before Venus is at superior conjunction behind the Sun, Mercury by coincidence is at inferior conjunction between the Earth and Sun. So as Venus is about to emerge in the evening sky, Mercury will soon appear in the morning sky.
- June 3 Tue.: The Moon is new.
- 7 Sat. evening: The crescent Moon is below Mars with the Beehive cluster to the lower right.
- 8 Sun. evening: The Moon is below the star Regulus with Saturn above them.
- 10 Tue.: The Moon is at 1st quarter.
- 11 Wed. morning: The year's earliest sunrise at latitude 30 degrees N.
- 13 Fri.: Friday the 13th, an unlucky day for the superstitious, but they're in luck as this is the only one this year.
- 18 Wed.: The full Moon is called Rose Moon, Flower Moon, and Strawberry Moon.
- 19 Thu.: Summer solstice, the year's longest day, marks the beginning of summer.
- 20 Fri. morning: The bright gibbous Moon is below Jupiter.