Remarkable images of Moon passing in front of Earth

[Northern_Piper]

@beowulff

Explain that, flat-earthers!

CGI.

It’s CGI all the way down.

[Northern_Piper]

Seriously, this is way cool. Thanks for sharing, ** Elendil’s Heir**!

[Northern_Piper]

@Ale

Ipresume that satellite is parked at the L1 point, to be able to look down on Earth in permanent sunlight

Ah, that explains it. I was trying to think how they could keep a satellite stable that far out, well past the geo-stationery orbit.

[CalMeacham]

@Ale

NASA is part of the conspiracy, duh!

I presume that satellite is parked at the L1 point, to be able to look down on Earth in permanent sunlight; I’d love to see a time lapse over weeks or months of the Earth rotating and the weather developing from that point of view.

This does indeed seem to be the case:

Deep Space Climate Observatory (DSCOVR), launched on 11 February 2015, began orbiting L1 on 8 June 2015 to study the solar wind and its effects on Earth.[18] DISCOVR is unofficially known as GORESAT, because it carries a camera always oriented to Earth and capturing full-frame photos the planet similar to the Blue Marble. This concept was proposed by then-Vice President of the United States Al Gore in 1998[19] and was a centerpiece in his film An Inconvenient Truth.[20]

Lagrange point

The L1, L2, and L3 points are technically unstable, but apparently you can put things in weird orbits about those points that are for all practical purposes stable.

[gnoitall]

@CalMeacham

The L1, L2, and L3 points are technically unstable, but apparently you can put things in weird orbits about those points that are for all practical purposes stable.

Not really stable. Spacecraft in the most common kind of L1 orbit have to expend stationkeeping energy (thrust, usually) or else the orbit will eventually diverge and the spacecraft will depart the Lagrange point. I’m trying to get a handle on how long an uncorrected L1 Lissajous orbit lasts, but haven’t found any primary sources. Just from how missions are planned, it’s gotta be shorter than the durations of the missions posted out there, since they all seem to go with stationkeeping delta-v on hand.

[CalMeacham]

@gnoitall

Not really stable. Spacecraft in the most common kind of L1 orbit have to expend stationkeeping energy (thrust, usually) or else the orbit will eventually diverge and the spacecraft will depart the Lagrange point. I’m trying to get a handle on how long an uncorrected L1 Lissajous orbit lasts, but haven’t found any primary sources. Just from how missions are planned, it’s gotta be shorter than the durations of the missions posted out there, since they all seem to go with stationkeeping delta-v on hand.

You musta missed that I said “for practical purposes stable”, and that they are technically unstable.

[Lumpy]

Also, in case there’s any confusion, we’re talking about the Sun-Earth L1 point, not the Earth-Moon L1

[Lumpy]

@Meurglys

You row out into the middle of the ocean and at high tide you put up a ladder, climb up it and jump down on to the moon!
Italo Calvino said so in The Distance of the Moon in his Cosmicomics collection! Don’t recall sea monsters being mentioned at all.
The first link here is the text as a pdf

Unfortunately, the ladder method is now considered too hazardous.

[Elendil_s_Heir]

@Northern_Piper

Seriously, this is way cool. Thanks for sharing, ** Elendil’s Heir**!

Glad to! I always appreciate a reminder of our proper place in the Universe.

[LSLGuy]

@Ale

…
I presume that satellite is parked at the L1 point, to be able to look down on Earth in permanent sunlight; I’d love to see a time lapse over weeks or months of the Earth rotating and the weather developing from that point of view.

NASA thought of that.

Here you can watch each day’s rotation as a slideshow of a dozen stills: http://epic.gsfc.nasa.gov/

I go there every morning and see how the planet did yesterday. If you go every day you’ll notice that some slides are missing some days. And occasionally a day or two is missing. I guess the pretty pix aren’t a big priority compared to the actual scientific data.

But it was really cool to watch this typhoon form, wander around the Pacific, then dissipate: SAIC | Digital Transformation

[Whiskey_Dickens]

@CalMeacham

The neat thing about that image is that it’s showing you the so-called far side of the moon fully lit by sunlight.

What do you mean by “so-called”? Did you mean to say “so-called dark side of the moon?”

[Kinthalis]

@MEBuckner

A dramatic illustration that the Moon is actually not very shiny. We’re used to seeing it all on its own, most often against the backdrop of the dark night sky, and not in front of a shiny blue planet, so we think of it as this brilliant silvery-white object rather than the dark gray world it really is.

Yeah, holy cow, it’s dull and grey and dark and ugly.

Is it really just the contrast with the night sky that makes it look so shiny? Maybe it only bother’s to pretty up the one side.

[CalMeacham]

@Whiskey_Dickens

What do you mean by “so-called”? Did you mean to say “so-called dark side of the moon?”

Either is “so-called”. But “Dark Side” is, I think, misused in this context.

[Whiskey_Dickens]

@CalMeacham

Either is “so-called”. But “Dark Side” is, I think, misused in this context.

I guess I’m just confused because there IS a far side of the moon, so adding “so-called” seemed odd. Nevermind I guess!

[Lumpy]

@MEBuckner

A dramatic illustration that the Moon is actually not very shiny. We’re used to seeing it all on its own, most often against the backdrop of the dark night sky, and not in front of a shiny blue planet, so we think of it as this brilliant silvery-white object rather than the dark gray world it really is.

Which makes me wonder how dazzling the moon would be if it were as white as, say, beach sand.

[Napier]

@Lumpy

Which makes me wonder how dazzling the moon would be if it were as white as, say, beach sand.

If it were Venus at that distance, we would never have invented headlights.

I mean, we would never have invented headlights because the tides would wash our cars off the road. Even in the middles of continents.

Tides of lava, that is.

But still, it’d be quite well illuminated.

At least, when it was some time around the full moon.

[whitetho]

I don’t remember the exact wording, but when this photo was first released one article had the headline of something like “Obnoxious Moon Spoils Perfectly Good Photograph of Earth”.

[LSLGuy]

@Whiskey_Dickens

I guess I’m just confused because there IS a far side of the moon, so adding “so-called” seemed odd. Nevermind I guess!

But from the POV of the pix taken from L1, that’s the close side of the Moon.

[LSLGuy]

@Lumpy

Which makes me wonder how dazzling the moon would be if it were as white as, say, beach sand.

The moon’s albedo is about 1/3rd that of beach sand. So a Moon made of beach sand would appear about 3 times as bright as the real one does.

[WildBlueYonder]

@gnoitall

THIS LOOKS SHOPPED. I CAN TELL FROM SOME OF THE PIXELS AND FROM SEEING QUITE A FEW SHOPS IN MY TIME.

seems so to me too :eek:
Where b all the space junk flying around up there?? :dubious: