Day 549 – Jupiter

There is an entire internet’s worth of information out there if you know where to look. There’s actually no excuse for not knowing stuff now if you have a device and a connection. Look at Friday evening for example.

There, up in the Eastern sky (near the top) was Jupiter. I knew this because I’d wondered what the shining star in the East was over the weekend, and I’d looked it up, before looking up at it.

As a bit of a demo, we got the tripod out, aimed and shot, hoping to get the four Galilean moons in the picture. It’s a quick and dirty image: I suppose I could have Googled for the best settings for this sort of thing, but as I say, this was a quick post-braai thing, and – much as I knew that the moons might be there – I picked the settings from my experience, rather than finding a site on the net.

Here’s what we got:

It’s not going to win any awards, other than maybe the one for demonstrating the four Galilean Moons of Jupiter to a few kids (and a couple of adults) after an early evening braai.
If I had tried harder or had more time, I could have done better, but that’s really not this was about. This was “That one there is Jupiter. Let’s see if we can see its moons and then get back to standing around the fire before I fall asleep.”

But then come the questions: How far away is that? How long will the light take to reach us? Which moon is which?

I can do a medium-rare rump over the coals and I can manage some functional camera settings, but I had to turn to the internet for these answers.

Currently, (current to when this was taken) Jupiter was 627.85 million kilometres away. That’s over four times the distance to the sun. I did a rudimentary calculation and that means that with light traveling (as it does) at 300000km per second, the light from Jupiter takes 35 minutes to get to us.
We’re essentially looking at a snapshot of Jupiter as it was just over half an hour ago.

But which moon is Io, or Europa, Ganymede or Callisto?
Well, surely there isn’t a site that can tell you that for any given moment?

Of course there is.

All I had to do was to pop in the date and time that the image was taken, allow for our longitude, and make sure they knew I was using an Erect System (stop it).

So, from the top down on our photo are: Callisto, Europa, Io, Jupiter and Ganymede. All taken from a well-lit suburban back garden, with a basic camera and lens, and all informed by the internet.

It’s not just there for being shouted at by anti-vaxxers.
Some of it is quite useful.

Voyage of the Moons

Well, this is fairly amazing.

“Software engineer, planetary and climate data wrangler, and science data visualization artist”, Kevin Gill has – as far as I can make out – melded together images from the Cassini spacecraft you may remember it from this post) during its journey past Jupiter and Saturn, and made them into a mini video:

The silence makes this all the more powerful, for me.

First up are Io and Europa passing over Jupiter’s Giant Red Spot (has anyone suggested using an ointment containing either salicylic acid or benzoyl peroxide?), followed by Titan moving past Saturn’s rings, seen as a thin line, edge on.

It’s all rather mesmerising. The latter, especially, has a really otherworldly feel to it. I mean, I am aware that these are bother very clearly other worlds, but I’m sure you get what I mean.

Original link here (creative commons says help yourself – thanks, Kevin).
The rest of his photostream looks equally impressive.

Awkward questions

Awkward questions are going to be asked of the Indian Army, as it was revealed that they had been tracking over 320 unidentified flying objects over six months on the disputed Himalayan border between India and China. These were believed by the Indians to be Chinese Spy Drones and raised the tensions on the border. Worrying times:

Tensions have been high in the disputed Himalayan border area between the two nations in recent years, with India frequently accusing its neighbour of making incursions onto its territory. Things came to a head during a stand-off in April when Chinese troops were accused of erecting a camp on the Indian side of the de facto boundary known as the Line of Actual Control (LAC). By that stage, Indian troops had already documented 329 sightings of unidentified objects over a lake in the border region.

Except, it turns out that they weren’t actually Chinese Spy Drones at all. They were planets.

No, the Chinese hadn’t roped in Jupiter and Venus to assist in surveillance of the Indian troop movements; the planets were just doing their thing in the sky, as they do and the paranoid Indians erroneously identified them as spy planes.

I know. This sort of thing sounds implausible, but it happens, so here’s my quick guide to distinguishing between Chinese Spy Drones and Jupiter.

Firstly, there are some similarities: both are unmanned.

But that’s where it ends. A Chinese Spy Drone is, at most 5 m long. Jupiter has a radius of 69,911,000 m. It is a whole lot further away though, so it can look smaller.
A Chinese Spy Drone may weigh up to 2000 kg. Jupiter, at our best guess (no-one has found a bathroom scale large enough) weighs
1,898,000,000,000,000,000,000,000,000 kg. Again, it’s ever so slightly larger than what you thought you were looking at, Private Gupta.

To be honest, this should be enough for someone to reasonable tell the difference between a Chinese Spy Drone and Jupiter, but just in case it’s not, only one of them would be taking covert surveillance video of your military positions.

And it’s not Jupiter.