You won't have to get out your telescopes to see Mars, Venus and the moon put on a show, Jan. 31.
The three celestial objects will be exceptionally close to each other on Tuesday night in a rare celestial treat called a conjunction.
[...] Kief says the best time to watch the conjunction is after sunset, starting at 8 p.m. PT. [Editor's Note: UTC-8]
He says to identify Venus, look for the glowing object that has a red and yellow tinge to it. Venus will shine slightly brighter than Mars, since it's closer to the Earth. Mars has an orange and red tinge to it.
And remember, if the celestial object you're looking at twinkles, it's probably not a planet.
(Score: 2, Informative) by Anonymous Coward on Tuesday January 31 2017, @02:00PM
Why teach people such stupid stuff. Venus
1) Is about half the distance to the Sun so gets hit with ~4x more light per unit area
2) Has an albedo ~3x that of Mars, so reflects that much higher a percentage of the light
3) Has ~4x the surface area of mars so reflects that much more light
So it will be ~48x brighter, having nothing to do with the current distance from Earth.
(Score: 0) by Anonymous Coward on Tuesday January 31 2017, @02:54PM
Well, what about the inverse square law? Surely, being closer to the Earth does indeed help its brightness, too.
(Score: 4, Informative) by isostatic on Tuesday January 31 2017, @02:57PM
I haven't looked as to the relative positions of Mars and Venus, but for the last couple of months I've been looking at Venus/Mars/Moon whenever there's no clouds (sadly quite rare). You can just about pick out mars in my town (findable thanks to the position of venus/moon), but Venus is easily spottable.
However I'm not sure you can multiply those points. When Earth is directly between Mars and the Sun, 100% of the surface facing Earth is lit, and it's about as close as it gets. We never see 100% of Venus lit, as it would be behind the sun. When it's mostly lit but just visible above the Sun's corona, it's on the opposite side of the sun, so distance is Earth-Sun-Venus.
Venus-Sun: 110mkm
Earth-Sun: 150mkm
Mars-Sun: 205mkm
Earth-Venus at maximum reflectivity: 260mkm
Earth-Mars at maximum reflectivity: 55mkm
As it happens, venus is at its brightest when it's a crescent. When it's surface is 100% reflective, it's actually really dim! When it's closest, likewise it's really dim (invisible even)!
(Score: 0) by Anonymous Coward on Tuesday January 31 2017, @04:02PM
Yes, the phase will be yet another huge factor besides distance from the Earth. I also don't feel like working it all out right now though.
(Score: 2) by bob_super on Tuesday January 31 2017, @06:12PM
Someone did the math and wrote in a newspaper that Venus would keep getting brighter until about the 15th of February.
Then, as it gets closer to Earth, the crescent will shrink fast and reduce the reflected light.
Even if it's cloudy today for the conjunction, it's still not too late to notice how bright Venus is (the dim moon crescent is growing though).
(Score: 2, Disagree) by DeathMonkey on Tuesday January 31 2017, @06:36PM
I love that the AC decrees "Fake News" based on a ridiculous back of the envelope calculation. Meanwhile, iso just goes outside and looks. +1 for empiricism.
(Score: 0) by Anonymous Coward on Tuesday January 31 2017, @07:54PM
If you read more carefully, you will see isostatic added a fourth factor of "phase" that can dominate the apparent relative brightness of Venus/Mars. He is not supporting the misleading claims of CBC that Venus is brighter because it is "closer to the Earth".