Within the motion pictures, this is when the spaceship lands. A door opens. Eerie-inexperienced lights flood the roadside. One thing alien steps out ... and you've got a Close Encounter. Time to dial 9-1-1!
Relax. It is solely Venus, the second planet from the Sun.
Right: Venus and the Moon beam by some trees in Brittany, France. Photograph credit score: Laurent Laveder.
Venus is the brightest of all planets. It makes Sirius, the brightest star within the night sky, look feeble. At sunset Venus materializes close to the western horizon the place it may well beam through bushes and make you suppose you are being ch
ased by something from outer space. No surprise so many people name 9-1-1 to report a UFO once they see it.
This week Venus (magnitude -4.5) is at most brightness. It is eight times brighter than the planet Jupiter (magnitude -2.3), 23 times brighter than Sirius (magnitude -1.1), and 275 instances brighter than the planet Mars (magnitude +1.6). Venus can really solid faint shadows; solely the Sun and Moon outshine it.
Why is Venus so brilliant? It's a cloudy world, only slightly smaller than Earth, and people clouds reflect virtually all the sunlight that hits them. The reflection appears especially intense this week as a result of Venus is getting near Earth: it is only 72 million km away--only a hop, skip and a soar on the vast scale of the solar system.
Venus' clouds hide the planet's surface. Even the biggest telescopes on Earth cannot see what lies below. But if in case you have a small telescope or binoculars, take a look at Venus anyway. There is something to see: Venus appears to be like like a fat grey banana.
Just like the Moon, Venus has phases. It can be full, gibbous, half or a crescent. These phases occur for the same motive that Moon phases do: geometry. One side of Venus is sunlit (the "dayside"). The opposite aspect is darkish (the "nightside"). As Venus orbits the Sun it turns one aspect, then the other, towards Earth. For the time being, Venus is popping its nightside toward us. We will see solely a sliver of the dayside--hence the crescent.
In one way Moon-phases and Venus-phases differ: The Moon is bright when it is full, and dim when it is a crescent. Venus is just the opposite. It reaches biggest brilliancy at crescent phase. A full Venus, then again, is dim. Strange however true.
The diagrams below show why. Venus is full when it's on the other aspect of the Sun. It's dim then as a result of it is away. Venus is a crescent when it is nearby--huge and bright.
Here's something to consider whilst you're looking at Venus this week: that delicate, stunning crescent is a hellish world. The planet's bone-dry floor is sizzling sufficient to soften lead. Venus' environment, 90 instances heavier than Earth's, is nearly pure carbon dioxide, a greenhouse fuel that traps solar heat. The thick blanketing clouds don't help; they trap warmth, too, and they're made of sulfuric acid. Robotic-spaceships sent to Venus have landed, but they never last long. Russia's Venera thirteen lander operated for 127 minutes--the all-time record--earlier than being overwhelmed by the acid, the heat, and the crushing strain of Venus' atmosphere.
And also you thought Venus was scary when it was just a UFO.