I went out Saturday morning to look for the recently-discovered comet C/2018 Y1 (Iwamoto). It beckoned from the the tail of Hydra the Sea Serpent. I found it with some difficulty because the comet was neither bright nor high up in the sky. While I like bright comets best, they’re all welcome in my front yard. When a new one is discovered, faint or no, if it’s within range of my telescope, I’ll get up at any hour just to be part of the welcoming committee.
But that’s not what I wanted to talk about today. About two fists to the left of the faint fuzz, Venus blazed like a fire in the treetops. Others have remarked on its brilliance including a couple of my neighbors who get up early to go to work. While lots of us have seen this brightest of planets before, a few things set its current appearance apart from some others. First, Venus rises well before the sun. In fact, the planet reaches greatest elongation today (Jan. 6), so it’s as far west of the sun as possible, all of 47° or nearly five fists. That puts the planet in a dark sky well before sunup.
Second, it’s only a few tenths of a magnitude fainter than it was at peak brilliancy, which occurred last September. Sunrise time also comes into play. Many of us are up by 6 or 7 p.m. for work or school, so we can’t help but notice the planet. For me its pull is irresistible. If you’re out an hour or two before sunrise, you’ll also notice a lesser but still bright light about a fist to the lower left of Venus. That’s Jupiter.
Starting tomorrow, Venus will begin to slowly make its way back east in the sun’s direction. At the same time, Jupiter is moving westward in the opposite direction as it climbs higher in the morning sky. You can guess what’s going to happen — the two planets will collide! Just kidding. But they will be in or near conjunction from Jan. 20-25. Closest separation happens on Jan. 22 when the duo will be slightly less than 2.5° apart. What a sight that will be!
Venus has the hottest surface temperature of any planet in the solar system. Its basaltic lava crust bakes at over 800° F (426° C) under a perpetually overcast sky scudded by clouds made of sulfuric acid droplets. Venus’s atmosphere is 90 times denser than Earth’s and composed of 96% carbon dioxide, making the planet a scorching, crushing, toxic place. Although closer to the sun than Earth, the clouds block direct sunlight except perhaps when they temporarily thin over this or that location. Despite the overcast, there’s still plenty of light at Venus, the equal of a cloudy day on Earth but of an altogether different color. Filtered by atmosphere and clouds, everything appears a sickly orange. It would be hard to imagine a more hellish place, yet the surface, as revealed by the Venera landers, looks plainly volcanic and rather earth-like minus anything alive.
Next time you see Venus, reach your hands out and imagine the radiant heat coming off this brilliant but baking planet. See more Venera images here.