Back so soon? Venus, lately of the evening sky, has returned to view in the morning sky after speeding north of the sun during conjunction on March 25. The transition from morning to evening is swift because the planet is between the Earth and sun and relatively close to us — about 26 million miles. Its proximity means it appears to move faster and cover more ground, swinging from one side of the sun to the other in a hurry. Just like an airplane that takes off in front of you compared to the same plane 25 miles away and 35,000 feet high, the closer something is, the faster its appears to move.
Just the opposite happens when Venus transitions from morning back to the evening sky. Then, the brilliant planet lies on the opposite side of the sun from Earth. It’s much further away — 158 million miles — and appears to move much more slowly, taking weeks to “separate” from the sun and finally show in the west after sunset.
To see Venus now, you need only face east about 35-45 minutes before the sun comes up and watch for a single bright star against the twilight glow. Be sure you pick a place with a good eastern horizon. Bring binoculars and you’ll see the planet as a wiry crescent. The crescent has reversed direction compared to its evening appearance. Its horns point west instead of east.
Venus and Mercury both never get too far from the sun. They can’t because they both lie inside Earth’s orbit. They may swing east or west of the sun but neither planet can get around behind us. Only a superior planet can do that. Don’t mistake Mars, Jupiter and the rest for snobs based on that description. That’s what astronomers call all planets that orbit beyond the Earth. Superior planets can line up behind the Earth in this order: sun-Earth-planet. When that happens, the planet is directly opposite the sun in our sky: it rises at sunset, stays up all night and sets at sundown. No, I’m afraid Venus and Mercury can’t do that.
The next planet to line up behind Earth at “opposition” will be Jupiter on April 7. Already, it’s up in the east around 9:30 and really looks fantastic around midnight high in the southeastern sky.
The sun illuminates all the planets, making them visible to the eye and telescope. Throw a giant invisibility cloak over our star and the planets would disappear from view … unless you had an infrared telescope, which “sees” an object through the heat it emits. Heat is simply another form of light. A radio telescope could also spot the planets, radio being yet another form of light.
Speaking of heat, the sun’s the hottest thing in the neighborhood and has recently been shooting off some powerful flares. Energetic ultraviolet light and X-rays’ effects on our upper atmosphere have caused occasional shortwave radio transmission blackouts here on the planet. But it’s unclear at this point whether auroras might result from the activity. Likely not as all the flares were directly off the sun’s edge and away from the Earth. Photos of the two big sunspot groups but especially region 2645 clearly show them strutting their magnetic stuff with material arranged around them just like iron filings around an ordinary bar magnet but on a grand scale.
Both the filings and ionized (electrified) gases in the sun’s atmosphere arrange themselves in the shape of the magnet’s magnetic field with a north pole on one end and a south on the other. How interesting to see something familiar play itself out across tens of thousands of miles on a star 93 million miles away.