Mark McCaughrean1d ago

You'll likely catch this image a million times in your various feeds: Earth as seen by Reid Wiseman from Artemis II en-route to the Moon.

My first thought? That's *really* noisy 🧐

But then I realised – it's the *nightside* of Earth, illuminated by the almost full Moon, not the Sun 🌕

The bright limb at lower-right is where the dayside starts, & the fact that you can see aurorae, airglow, & cities in Europe, Africa, & S & N America also gives the game away.

Cool.

#Photography #Artemis

Show threadsaarmuller1d ago
@markmccaughrean What do you mean by the bright limb at lower-left?
Show threadMark McCaughrean1d ago
@saarmuller I mean that that's a typo – the limb at lower-right. Ugh – will edit.
Show threadsaarmuller1d ago
@markmccaughrean Right!
Show threadsaarmuller1d ago
@markmccaughrean And also, I think that is where the day ends (the north pole is at the bottom), very confusing.
Show threadMark McCaughrean1d ago
@saarmuller The poles are where the aurorae are, broadly speaking, at upper-right & lower-left, so the terminator is more or less north-south, a little biased north, as you’d expect a couple of weeks after the equinox.
Show threadsaarmuller1d ago
@markmccaughrean What I mean is: the bright rim is on the westside, so the end of the day, not the start of dayside. What am I missing?
Show threadMark McCaughrean1d ago
@saarmuller Oh, in that sense – yes, it's the evening terminator at the end of the day, not the dawn terminator. Good point. I just meant is was the start of the dayside, as in where the dayside "is", not which time of day it was per se.
Show threadsaarmuller1d ago
@markmccaughrean That's what I meant by "very confusing"! (Combined with the left-right error, the left WAS the start of day side, the dawn side)
Show threadMark McCaughrean
@saarmuller 🙃👍
Apr 3 at 6:34pmWeb