Monday, May 28, 2018

The brightness on distant planets

I watched Stargazing on the ABC last week, and enjoyed it enough.  (The "world record for number of people looking at the moon" seemed rather pointless, but people seemed to support getting out and it was a science-y thing, so what the hey...)

Back here in my backyard, while I wait for the dog to finish its wee before going to bed, I've been noticing how bright Jupiter and Mars seem to be at the moment.   The brightness of Jupiter in particular put me in mind of the question of how bright things would seem if you were an astronaut on one of its moons.  I remembered that this had been dealt with in a Robert Heinlein juvenile, where he had written that the eye on Earth is flooded with light during a bright day and just ignores the excess (so to speak); the result being that even on a Jovian moon, daylight would still look pretty much as bright as a day here.

I wondered last week if this was right, and have now just Googled the topic.   It would seem to be not too far off the mark, according to explanations at Quora and this table, which indicate that being on moon of Jupiter would be brighter than a hospital operating theatre.   They're all pretty bright, aren't they?  (Oddly, it makes one comparison indicating that being on Neptune the brightness would be able the same as "typical public bathroom".)

Things would be starting to look pretty dim at Pluto (somewhere between "public bathroom" and "typical night lit sidewalk"), but you would still be able to see colours.  In fact, this very neat NASA web page lets you enter your location, and come up with the next time that the light outside would look like midday light on Pluto!   Neat.  For me, it will be tomorrow morning at 6.24 am.   (Sunrise is 6.29am.)   I know the sky is still pretty bright at that time, but I will take particular note tomorrow while at the breakfast table.   I hope my son is still there too, so I can inflict some unwanted science on him.  I love doing that to my children....

1 comment:

not trampis said...

I like Brian and her. Brian has lots of personality and enthusiasm on the subject and she somehow reminds me of Stana Katic!!