Venus and Jupiter Conjunction June 30, 2015

On June 30, 2015, Venus and Jupiter lined up very closely in the night sky as seen from Earth, just 0.3 degrees apart — closer than the diameter of the full moon!

The day of the conjunction was muggy and cloudy, and I really didn’t expect to see them at all. To my surprise and relief, it cleared up and cooled off after nightfall.

You really don’t notice how much brighter Venus is than Jupiter until they’re right next to each other. Jupiter is much bigger, so it reflects a lot more sunlight, but it’s also a lot farther away.

Also, that conventional wisdom about how stars twinkle, but planets don’t? Not true. In turbulent air, planets absolutely twinkle.

Venus and Jupiter two days after the conjunction

Two nights later on July 2, I walked outside facing west. The sky near the horizon was still orange, but the two brightest planets were clearly visible against the deepening blue.

And just to show you how fast Venus moves across the sky, here’s the view 10 days before the conjunction, on June 20:

The moon, Venus and Jupiter over Mimi's Cafe

I didn’t have a tripod handy that night, so I used the top of the car, which conveniently lined up with Jupiter and the chimney.

Yesterday I looked at the moon and Jupiter and thought, there’s going to be another conjunction tomorrow, isn’t there? Then I forgot, but fortunately I had to make a grocery run and looked up.

For this second shot, I zoomed out and let it overexpose the moon so I could get the bright star Aldebaran in the photo as well. It was a bit easier than the really good one in January, because the crescent moon isn’t as bright (less area shining at us), so it didn’t overwhelm the stars and planet quite so thoroughly.

As I post this, it’s been about half an hour, so if you’re in the western half of North America and the sky is clear, you can walk outside RIGHT NOW and see this!

View 1: Jupiter is visible, but the moon oversaturates the camera. In the other: The moon is clear, but Jupiter is too dim to see.

I walked out to get the laundry tonight, looked up and saw the moon and Jupiter practically next to each other. I took a quick shot with the phone, then went back in to get a better camera. (Unfortunately, the best camera I have is in the shop right now.) The phone picture is at upper left, the camera picture at lower right.

Nothing makes you appreciate how bright the moon really is like trying to avoid overexposing it without making the second brightest planet disappear.

NeptuneThis morning I saw some wavy clouds that reminded me of the patterns you see in pictures of Jupiter. I started thinking about gas giant planets, and had an odd moment of realization: when I was a kid, astronomy books didn’t have actual photos of Uranus or Neptune. They couldn’t have — there weren’t any! There were nice photos of Jupiter and Saturn from the Voyager missions, but Voyager 2 didn’t reach Uranus until 1986, or Neptune until 1989.

The really weird thing, though: modern astronomy books do have photos of Neptune — but the ones for general audiences probably all use the same picture I got as a framed poster when I was in high school. We haven’t been back in 20 years. Jupiter and Saturn have gotten a lot of attention, partly because they’re a lot closer and partly because their ring and moon systems are so fascinating. So we have a more continuous view of those planets and how they change over time.

Neptune? One snapshot (metaphorically speaking) of the planet from 20 years ago. Everything before and everything since then has been done with telescopes. Even the Hubble barely has the resolution to tell that the Great Dark Spot broke up sometime between 1989 and 1994. That’s something that maybe shouldn’t have surprised anyone, given how quickly storms form and dissipate on Earth, but back in 1989 it seemed so much like Jupiter’s Great Red Spot (going on 400 years or longer) that it was easy to think it too would be persistent.

It’s a good reminder that the universe beyond Earth does change with the passage of time…even on a human scale.