Once again, if you’ll look west after sunset, you’ll find the moon and Venus near each other – dazzlingly bright. The planet Venus is the third-brightest heavenly body to light up the sky, after the sun and moon. And Venus is nearly at its brightest now for this evening apparition. Check them out tonight!
Moon and planet Venus on April 24, 2012 from Arizona from EarthSky Facebook friend Cindy Rae.
Because Venus orbits the sun inside of Earth’s orbit, we see this world going through the whole range of phases – much like our moon. Both the moon and Venus are evening crescents right now, though you need a telescope to see the crescent Venus. Try looking at evening dusk before the glare of Venus becomes too overpowering. Tonight, Venus is a bit more than 30% illuminated by sunlight.
Phases of Venus diagram
Like the moon, Venus shows phases as seen from Earth. This charts helps explain why.
Unlike the evening crescent moon, which is waxing toward full phase, the evening crescent Venus is waning toward new. That’s because Venus revolves around the sun while the moon revolves around the Earth.
Venus completes its cycle of phases – from new Venus to new Venus – in a mean period of 584 days. Amazingly enough, Venus passes in between the sun and Earth (at new Venus) 5 times every 8 Earth-years.
As seen from Earth, Venus almost always passes to the north or the south of the solar disk when it sweeps between the sun and Earth. But not this time. On June 6, 2012 Universal Time (June 5 for the Western Hemisphere) Venus will transit – swing right in front of the solar disk – appearing for several hours as a dark dot moving in front of the sun.
Last transit of Venus in 21st century will happen in June 2012
Eye protection is absolutely essential for watching a transit of Venus. Contact an observatory or astronomy club near you to see if a public showing may be available.
Transit of Venus June 8, 2004. During a transit, Venus appears as a dark dot moving across the sun's face. The last transit of Venus in this century will be June 5-6, 2012. Image Credit: Wikimedia Commons
At the June 5-6, 2012 transit, Venus will travel from east to west across the disk of the sun. Image credit: Fred Espenak NASA/GSFC.
Click here for a larger chart of Venus transit
Transits of Venus are extremely rare. The last one took place on June 8, 2004. The upcoming transit on June 6, 2012, will be the final transit of Venus in the 21st century (2001-2100). If you can wait that long, there will be two transits of Venus in the 22nd century (2101-2200) on December 11, 2117, and December 8, 2125.
Bottom line: Let the waxing crescent moon show you Venus on the night of April 25, 2012. Tonight, Venus appears through telescopes in a waning crescent phase. The planet is preparing to pass directly in front of the sun on June 5-6, 2012 in the last transit of Venus in this century. Afterwards, Venus will come back into view in Earth’s predawn sky.
