[_fw]

Am I losing it? They can’t be seeing the far side of the moon right now, because they haven’t adjusted course to go round the far side of the moon yet…

So does this suggest the BBC is wrong and it’s the side of the moon we’re used to seeing, but just it’s “dark”?

But then the astronauts are saying it’s weird seeing the moon in a whole new light (excuse the paraphrasing pun).

I don’t understand.

[roelschroeven]

Have a look at the tracker at https://issinfo.net/artemis.html

They're already at a point where they see the moon from a different angle than we see it from Earth, enough to see a bit of the side that we can't see from here.

[riazrizvi]

It would be good for the interviewer to ask about this! I imagine a lot of people are pretty confused by the basic geometry. Thanks for explaining.

[addandsubtract]

It took me this diagram to realize they're shooting to where the moon will be, when they cross its orbit, and are not flying straight at the moon. /facepalm

[roelschroeven]

No worries. I played Kerbal Space Program so that shouldn't have surprised me but it did, and it took me a few seconds before the penny dropped.

[pierrec]

>they haven’t adjusted course to go round the far side of the moon yet

They did, 3 days ago! Maybe this is being pedantic (?) but the trans-lunar injection burn they did on April 2 put them on the complete trajectory including return to Earth. Though there are still possible correction burns that can be done to increase precision (the first 2 of these were already canceled).

[_fw]

I relish in the pedantry. Thanks Pierre

[beloch]

Imagine you're holding a ball with drawings on it. Hold it out at arms length and fix how it looks in your memory. Now bring it close to your face and move your head a tiny bit to the side. You're not seeing the whole back-side of the ball. Far from it! However, you are seeing some bits you weren't seeing before and the whole picture you can see now looks different than it did when the ball was at arm's length.

That's my guess. They're seeing parts of the dark-side of the moon because they're now close enough that they have a different viewing angle than we do on Earth. Remember, they're not flying straight at the moon. That's not how transfer orbits work.

[drjasonharrison]

"far-side of the moon"

There is no dark side.

[classic959]

"Dark side" is used to describe the part we never see from earth's vantage point, not a part that gets no light from the sun. Definitely confusing for the uninitiated though.

[bdbdbdb]

I was also very confused, but after some reading I figured it out.

> In an interview with NBC News from space, NASA astronaut Christina Koch described seeing the moon out the window of the Orion capsule and realizing that it looked different from what she was accustomed to on Earth.

> “The darker parts just aren’t quite in the right place,” she said. “And something about you senses that is not the moon that I’m used to seeing.”

They are not on the other side of the moon seeing the full dark side, but from their position they're seeing the moon at a slight angle, meaning that SOME of what they now see is "the dark side", or the part we can never see from earth since the same side always faces us

[randomNumber7]

> “And something about you senses that is not the moon that I’m used to seeing.”

Almost philosophical /S

[implements]

Remember that they’re not flying towards the Moon but to a point in space where they and the Moon will be closest together in a day or two, hence the Moon is now ‘off to their side’ and they can see a segment of it that is hidden to Earth observers … I think.

Also, the dark side of the Moon is often illuminated but we call it dark because it’s also hidden from earth due to the Earth and Moon being tidally locked (the same side of each always faces the other body).

[drjasonharrison]

We call it "dark" because we are sloppy.

The same side of the moon always faces the Earth. If the same side of the Earth always faced the moon, then only one hemisphere would be able to see the moon. Since you can see the moon from everywhere on Earth (not at the same time...), we know that the same side of the Earth does not always face the moon.

Unless you're thinking of the "outside" of the Earth. /s

[classic959]

I think we call it "dark" because the term was coined when the English language was used in a more poetic sense - at least it seems like that to 21st century-me. "Dark" = "it has not been made visible to us".

I've just been reading Narnia stories to my son and lots of the language seems dated and initially confusing but very descriptive and more poetic. Even though that was just in the mid-20th century.

[ceejayoz]

They’re far enough out that they can see some stuff you don’t see from Earth. They aren’t seeing the entire far side yet.

Illustrated: https://www.reddit.com/r/Astronomy/comments/1sd797j/the_moon...

[gus_massa]

It got deleted now. It would be nice to see a new versions if abailable.

So, let's make some guess, but IANAA. Orion is in the middle of the trip going to the meeting point to the Moon in a quite straight line but the Moon is still not there. It will be there in 2 or 3 days, that is like 45° of the orbit.

  O                                                          .   .    o
  Earth                            >   .    .     .     .             Moon
                                   Orion                              in 3 days
                                                                    .
                                                                  .
                                                               .
                                                            .
                                                         .
                                                       .
                                                     o
                                                     Moon
                                                     now

Using some sloppy Math and sloppy Astronomy, I estimate that the difference between our point of view and their point of view is 20° or 30°. So the visible surface has like a 10% difference, that is consistent to call it a "glimpse". My estimation is also similar to the graphic posted in Reddit, but I'm not sure what was the problem.

I actually can't tell the difference in the photo to save my life, but I have a friend that is astronomer and I'm sure that if I show the photo to him, he could use a sharpie to mark the difference on my screen without any problem.

[syncsynchalt]

Take a look at https://issinfo.net/artemis.html

Your illustration is about right, but the angle they're catching now is even a bit further than you've shown.

[runjake]

Hence the use of first glimpse.

[mathgeek]

“First glimpse of the dark side of the moon” rather than “the whole dark side of the moon”. Title is pretty accurate for my understanding.

[AnduCrandu]

I think they're saying they can see a sliver of the far side, and that seeing the moon from a slightly different angle is weird having seen the near side so often. But they didn't really make that clear.

[randomNumber7]

Sounds like marketing speak.

[dreamcompiler]

> they haven’t adjusted course to go round the far side of the moon yet

No course adjustment is necessary (at least in the sense of an engine burn). The moon's gravity will sling them around and back toward Earth.

[Rebelgecko]

They've actually already on course to go around the moon for a couple days! There's been the option of performing some some minor course corrections to make sure they look back around to the right Earth orbit, but I think those haven't actually been necessary

Source: NASA's YT channel + way too many hours playing KSP. Skipping the course correction burn yesterday gave them the opportunity to try and unclog the liquid waste valve

[NetMageSCW]

They did that change a long time ago. They are on a course to go around the Moon from the TLI burn (trans lunar injection) Thursday at 7:49pm EDT. They don’t need any more burns for that.

[baxtr]

I think they could not communicate if they were really on the far side of the moon.

So I guess they see it differently than us, eg from the side but not from the back.