Why People Should Read

[Kelliezgirl]

In Neal Stephenson's Seveneves, the moon, for reasons unknown, breaks into seven pieces. As the orbit the earth, they collide with one another and continue to break down into smaller parts, until they disintegrate into millions of fragments too small to escape Earth's gravity well. As they descend into the atmosphere, the heat of their entry raises it by thousands of degrees, (possibly) incinerating all life on the planet.

I'd settle for a comet...

 

[TheLobster]

incinerating all life on the planet.

still waiting for the sequel.

 

[Five_Inch_Heels]

This is as opposed to, say, the Voyager spacecraft, now in interstellar space.

I believe there are more than one, but I don't recall which.

But yes, humans never have and likely never will escape Earth's orbit.

 

[Five_Inch_Heels]

In Neal Stephenson's Seveneves, the moon,

In the Twilight Zone episode Midnight Sun, the Earth breaks orbit and approaches the Sun, with expected consequences. Or ... is it moving away leading to a frigid outcome for all?

 

[SimonDoom]

In Neal Stephenson's Seveneves, the moon, for reasons unknown, breaks into seven pieces. As the orbit the earth, they collide with one another and continue to break down into smaller parts, until they disintegrate into millions of fragments too small to escape Earth's gravity well. As they descend into the atmosphere, the heat of their entry raises it by thousands of degrees, (possibly) incinerating all life on the planet.

I have to read this one. I finished Anathem last year, and I've read most of his books.

 

[JGittes]

Bit Ameri-centric.

I think the big contest will have to be which country can create robot fast food joints to be worthy of being uplifted to become one of the first outlets on Mars, not to mention the contract for in-flight catering.

Imagine the World Robot Cook-Off Challenge - a holographic Anthony Bourdain and various people taste-test the offerings from various machine-produced food stalls. Obviously I'll be hoping for Bossman's Robo Kebab and Beep Beep Falafel to be up there, along with a breakfast naan stall, a bao bun place and HAL's pie shop.

I'm afraid this has been definitively answered in the documentary "Demolition Man," and Taco Bell won the franchise wars.

 

[Five_Inch_Heels]

I'd settle for a comet...

Night of The Comet?


Fun flick.

Weird, but fun.

 

[TheLobster]

What does that have to do with anything? The Apollo and Artemis capsules were always in orbit around Earth, by which I mean that without some sort of acceleration they would take closed paths around it, not recede indefinitely.

No, they would not.

Every Apollo mission which reached the gravitational sphere of influence of the Moon, and now also Artemis II, have traveled far enough from Earth, and fast enough, that if the Moon wasn’t on their trajectory — and in some cases, they didn’t perform burns for insertion into lunar orbits — they would have (not so) happily continued on their way, away from the Earth, and become direct satellites of the Sun.

This is as opposed to, say, the Voyager spacecraft, now in interstellar space.

Yes, Voyagers et al. move fast enough to escape the gravitational sphere of influence of not just the Earth (like the moon missions) but also the Sun. They are (most likely) satellites of the center of the galaxy.

 

[Kelliezgirl]

Night of The Comet?


Fun flick.

Weird, but fun.

Dad would have gotten us Uzis.

 

[AG31]

You know, every so often I find myself pitying you when you post things here and it's clear that you're sad, old and lonely.

Then you say shit like this that is not only ignorant and completely tone-deaf, but needlessly rude for no good reason at all. If this is how you choose to interact with other human beings, then you absolutely deserve to be sad, old and lonely.

On-topic: If anyone wants to keep up with live transcription of Artemis II's progress along with some cool data, I've been following this very nifty-looking tracker. Space is awesome, and we're so lucky to be able to follow along with this trailblazing trip back to the moon.

When I click on the link it displays an empty purple screen and the little indicator slides left and right in the tab label and nothing happens...
Edit: Went back a few minutes later, and there it was! Thanks!

 

[AG31]

Funnily enough, although I'm very much into space myself — but mostly from the astronomy/cosmology/SETI/etc. angle, not day-to-day operations of space agencies like NASA — I almost missed the actual launch, because it's been postponed so many times that I eventually stopped paying attention.

One justification I can think of for not caring too much about it is that it's kinda stretch to call Artemis II a Moon mission. Yes, they're going in this direction, but they'll neither land on or orbit it, merely use it for gravity assist to return back to Earth. It's basically Apollo 13 sans the exploding oxygen tank (or Tom Hanks), except not even that since they'll pass the Moon away within many thousands kilometers rather than a bit over a hundred.

My understanding of this mission is that it's mostly for closely evaluating the impact of deep space travel on human body, since we haven't done that since the 70s and we now have rather better technology to do it. That's in addition to the more overrarching goal of routinizing the whole Earth-Moon travel thing and launching things beyond LEO.

I sometimes leave the TV on mute on Fox, just to find out what's being talked about on the other side via the chyrons. I walked into the living room just as the blast was beginning. Live is sometimes better that taped. Recorded... what's the right word now?

 

[BeechLeaf]

Linguistic musing on 'in orbit around': We say the Moon orbits the Earth, and the Earth orbits the Sun. That's the minimal scope of 'orbit' where it's a Keplerian ellipse. Yes, technically the Moon also goes around the Sun, but its path there is some kind of Ptolemaic Spirograph (hand-waving). Do people, or do experts, in fact commonly say the Moon orbits the Sun?

I think we would want to say that the Earth orbits the galactic centre, because here we're talking about us in relation to it, and in this context and scale the epicycles around the Sun are irrelevant minor adjustments, like precession of the axis.

 

[AG31]

Let's hope the space toilets are more reliable by then.

I dug into this a little, and apparently it was a frozen waste pipe that they thawed by turning that side of the capsule toward the sun. I'm not sure if it was successful.

But the BBC story was all about urine. No mention of what they do with poop. Just assume it's all together? How do you use a bag as backup for pooping?

 

[TheWritingGroup]

No, they would not.

Every Apollo mission which reached the gravitational sphere of influence of the Moon, and now also Artemis II, have traveled far enough from Earth, and fast enough, that if the Moon wasn’t on their trajectory — and in some cases, they didn’t perform burns for insertion into lunar orbits — they would have (not so) happily continued on their way, away from the Earth, and become direct satellites of the Sun.


Yes, Voyagers et al. move fast enough to escape the gravitational sphere of influence of not just the Earth (like the moon missions) but also the Sun. They are (most likely) satellites of the center of the galaxy.

You might want to check the easily-available orbital track of Artemis 2, showing it passing beyond the moon and returning without an engine burn.
https://exploredeepspace.com/wp-content/uploads/2020/02/Artemis_2_Trajectory.jpg

 

[TheWritingGroup]

Linguistic musing on 'in orbit around': We say the Moon orbits the Earth, and the Earth orbits the Sun. That's the minimal scope of 'orbit' where it's a Keplerian ellipse. Yes, technically the Moon also goes around the Sun, but its path there is some kind of Ptolemaic Spirograph (hand-waving). Do people, or do experts, in fact commonly say the Moon orbits the Sun?

The gravicenter of the Earth-moon system is outside the surface of the Earth. Technically, we both orbit that rapidly-moving point in space. Seen from "above" the solar system, the moon traces a somewhat wobbly orbit around the sun, never "going backwards" in an epicycle-like pattern. So ... yes.

 

[AG31]

But yes, humans never have and likely never will escape Earth's orbit.

One of my vivid childhood memories is my father explaining to me, with great confidence, why people could never travel to the moon. It's because the fuel would weigh more than the power of the blast to take off. I don't remember if he was alive for the first moon landing, but I'm pretty sure I never said, "I told you so."

Edit: On further reflection, I don't think the context of this conversation was the NASA program. I think it was Buck Rogers in the funny papers.

 

[Five_Inch_Heels]

And our system orbits the Milky Way which orbits something else.

You think you're sitting still on your couch, but ...




As far as decaying orbits, think Spacelab and a few other events.

 

[anthrodisiac]

The gravicenter of the Earth-moon system is outside the surface of the Earth. Technically, we both orbit that rapidly-moving point in space. Seen from "above" the solar system, the moon traces a somewhat wobbly orbit around the sun, never "going backwards" in an epicycle-like pattern. So ... yes.

The barycenter is actually within the Earth, about 5000km from the center. So while both objects orbit that point, the point is still within the Earth itself, hence why the moon is a satellite of the Earth. Pluto-Charon system has a barycenter outside both objects, technically making it a binary dwarf planet system.

 

[MelissaBaby]

Remnants of humanity survive on a hastily constructed space station.

 

[TheLobster]

You might want to check the easily-available orbital track of Artemis 2, showing it passing beyond the moon and returning without an engine burn.
https://exploredeepspace.com/wp-content/uploads/2020/02/Artemis_2_Trajectory.jpg

Yes, Artemis II didn't need an extra burn to maneuver around the Moon because it was conceived as a free-return mission. This means that the gravity assist around the Moon was essential for the spacecraft to turn around and go back to Earth. But this is just a characteristic of this particular mission, and I'm not sure how it supports the idea that they moon missions are still "in Earth's orbit."

To be clear, Artemis II's return is enabled by the Moon's gravity, not Earth's. Were the Moon not there when they needed it (they launched too early or too late and didn't correct), they would've gotten stranded in the interplanetary space. Here's a handy animation that depicts their trajectory; if you remove from it the Moon (green), it's clear that, post-launch, their trajectory is hyperbolic wrt Earth and the spacecraft would not return to Earth on its own.

 

[anthrodisiac]

Remnants of humanity survive on a hastily constructed space station.

"Ma'am, we're running out of duct tape!"

"God help us all..."

 

[TheLobster]

BTW I don't wanna look like I'm ragging on @TheWritingGroup specifically. The misconceptions like "Earth's orbit is a place" or "when the sky turns black, gravity stops!" are extremely easy to acquire if you watch pretty much any visual media that features space travel. Heck, I long harbored those myself, because films etc. either get this wrong, or they don't spend enough time to really showcase the consequences of kinematics in space.

The one movie that really drilled it in my brain that, as far as spaceflight is concerned, space is actually a six-dimensional, uhm, space, is Gravity (2016 I believe). If you watch it, you can really, viscerally grasp how it's all about Newtonian motion through vacuum (and how it's fucking terrifying). Wholeheartedly recommend it. (Apollo 13 is good and accurate, too, but it doesn't have nearly the same impact).

 

[TheLobster]

Remnants of humanity survive on a hastily constructed space station.

Oh, so you're just looking for The 100

 

[SandraMaus]

Yep. Dad rented a TV so we could watch Apollo 11, and as kids we watched the whole moon walk in the school hall.

I can vaguely recall the very blurry video feed from the first landing, then the later landings with the moon buggies. By that time the video feed was better.

The one that astonished me was the first Shuttle launch. I thought that was a game changer, which it was for a while. And then the really bad jokes started...

My parents grew up in East Germany. My dad told me that kids were not allowed to talk about watching the Challenger launch. They were as hyped about it as western kids. Because most people did receive West German TV. But as it was, the teacher was an astronaut and not a Kosmonaut teacher flying into space it was taboo. . It was afternoon in Germany when the shuttle blew up live on TV. My father told me how shocked some kids were at school next day and not allowed to talk to their friends about it.

 

[Ianus4]