The Space Thread

That's the older formation. This is the current one [pedantry].

The idea would be to move all space functions under its own branch.

Kurzgesagt made a video on lunar colonization. I was wondering what are the barriers to this goal besides impatient heads of state. And I want to ask for other opinions of the topic of lunar colonies.

With space colonization there's a bit of a catch-22. There isn't much of a point in building launch infrastructure to make such a thing really practical until there's actual industry in space. There isn't much of a point in making a moon colony unless there's better launch infrastructure and what have you.

The problem's unwinding itself slowly, but it'll be a little while.

x5 The solar observatory enjoys an excellent view of Holloman AFB and the White Sands Missile Range, some of the most sensitive military sites in the US. Espionage is the most likely cause of the closure.

x3 It isn’t really a bad idea, honestly, Trump is just the wrong president to do it.

Edited by archonspeaks on Sep 16th 2018 at 12:15:45 PM

I've wondered how big one planet needs to be to another for both to be totally destroyed with normal orbital speeds. Like if I were to send Mars and Earth careening towards one another by matching Mars' orbit, will it destroy the Earth? Or if I send Uranus into Jupiter

Actually, how close would Mars have to get to the Earth before its gravity alone starts to screw us over

The damage from a planetary collision would largely depend on the angle of impact.

A dead on impact from a Mars size body would almost certainly destroy the Earth; possibly not to the level of creating a new asteroid belt but it would definately fragment the Earth.

A more glancing blow to the Earth from a Mars size body however would leave it largely intact and has almost certainly already happened; that's the leading theory for the origin of the moon. It'd still wipe out all life, boil off the oceans, and return the Earths surface to a molten state but the earth itself would survive.

As for how close it'd need to be to get to be a problem probably much closer than you'd expect gravitational force decreases with the square of distance so it drops of really quick; you could probably drop Mars into orbit just outside Earths roche limit and the only real efects would be massive tides and the disruption of our satellite belt. Even inside the roche limit the primary issue would come from the millions of chixilub scale meteors it'd turn into rather than the gravity.

To actually get noticable effects on people from the gravity alone you'd probably have to have Mars be partially within the atmosphere at which point you have far far worse things to worry about.

Edited by Jaustin89* on Sep 26th 2018 at 8:56:15 AM

Like it ends up causing earthquakes, it causes the atmosphere to catch on fire, screws with the moon or some crazy heat event happens? How close would Mars have to be before civilization as we know it is doomed, ignoring of course how it might screw with the animals

For that matter, while removing planets from the solar system won't really affect Earth's orbit, if you removed them from history, for example Mars just vanishes 3.8 billion years ago, would it eventually alter the orbits over the eons? If so, how long would it take for the disappearance of a planet to have significant effect on Earth's orbit?

How very close are we talking about?

Edited by RJ-19-CLOVIS-93 on Oct 8th 2018 at 11:24:39 PM

Yes, if another planetary body got close to Earth it would cause earthquakes due to tidal forces and disrupt the moons orbits as the interloper's gravity starts interacting with it. As for how close Mars would have to get to doom civilisation. Very.

As for just hypothetically removing a planet from it's orbit at some arbitrary point in the past, it's hard to say. Orbital dynamics is a many body problem and is actually governed by chaos theory (mathematically speaking). And that's not even getting into stuff that can't be predicted, like Mars backstopping asteroids or comets that might have hit Earth. Jupiter does the bulk of that work but we can't really say that something that hit Mars wouldn't have hit Earth it Mars hadn't been there... sooner or later.

New Horizons is about to make it's flyby of Ultima Thule.

Here's the schedule of events:

I'm pretty excited for it since we probably won't have close up shots of an object further away from Earth for at least a couple decades. There aren't any other Kuiper Belt missions outside of the concept stage to my knowledge. Definitely going to try to catch the signal acquisition livestream since that's when we'll know if it made it past intact.

How close it's going to be?

Only 3,500 kilometres, apparently.

Just watched the livestream. New Horizons is alive and well and collected as much data as they were expecting.

We'll be getting the first high quality images this afternoon, though it will take several months to download all the science data from New Horizons.

The main problem with colonizing themoon is the steep initial cost (10 billion on up) and the relatively low return on investment, plus little if any justification in terms of national security, public health, or social issues. Plus, we could probably do it a lot cheaper with robots.

There are reasons to go to the moon, though in practice it's not practical yet. The thing to keep in mind is that we actually don't know what lunar gravity does to the human body in long-term. We know what zero gravity does, and we know what Earth gravity does, but not anything in between.

Robots doing it would actually be the best point. But good luck persuading any Government with that, because of the Anthropic Principle.

People still think that Space Exploration and relevant Technologies have to be done with Humans on the spot. Mostly because it's hard to empathise with machines.

And with a ton of competing interests for funding - well, only Privateers are going to be making any significant steps forward. Not Governments. Still, I have hopes.

Thats not how NASA is funded now, which is almost entirely automated probes. I could see putting a half dozen people in lunar orbit to direct the robots. Make the hab rotate for full grav and it becomes a testing ground for exploiting the rest of the solar system.

I wasn't referring to NASA. They'll continue with the best they can.

I was referring to other space agencies, like the ESA, ISRO, and JAXA. CNSA and Roskosmos probably won't have that problem, but I know very little about their internal functioning so that I can't really comment on them.

In any event, I don't think Lunar Colonization can be a single country job. It'll have to be a collective one if it has to work, if at all.

I suspect that Lunar Colonization won't be done by robots other than perhaps preliminary building - one, there will be a strong psychological motive for using humans (roller coasters and cruise ships are frequented by humans and not by robots, too), two, a colony by definition serves as human occupation area.

If there is money to be made on the moon, they will send whatever it takes to get the job done. If there isnt, then it wont happen regardless.

There are two advantages to sending people vs robots: people can do more complex tasks, and people are better at adapting to unexpected conditions.

Any robotic probe we send out can only do certain tasks it was designed for. If you want to do anything else, you have to send out another probe. Humans are way more flexible than that and can do any number of different things, especially if they have enough tools and materials on hand to build new tools as needed. That generally requires at least a semi-permanent presence (ISS style) if not an actual proper "colony".

Light-speed delay also becomes a factor for basically anything farther away than the moon. The moon has a round-trip delay of about 2.5 seconds, which is workable for near-real-time remote operation, but past that you're talking minutes or hours of delay, so rather than operating something directly you have to send a set of instructions and trust the thing to do it on its own. Putting humans there cuts the light speed delay to almost nothing, which shortens that command cycle considerably and allows you to do more things more easily in less time.

Plus, you know, there's also the "because it's there" aspect, which is real even if it's not entirely rational. There's value in setting a goal (like "human habitation of the moon/Mars/etc") and following it through to completion, even if the goal itself is arbitrary. You learn new things and develop new techniques to accomplish the goal, which then let you more easily do other, less-arbitrary things.

With the argument that "because it's there", I would argue that works for exploration missions, but not for colonization.

The Moon is both a great place to send robots and a great place to send colonists for the same reason: It's very close. It's close enough that you can operate a robot in almost real time. However, that also makes it an ideal place for colonization.

There is money to be made on going to the moon, also. The moon is filled with a lot of metals that are quite valuable. It isn't practical to colonize the moon with today's technology, but the more it improves the more practical it becomes and once it is practical there's plenty of reasons to go there.

We got higher-rez pictures of Ultima Thule. This isn't the highest resolution pictures we'll get, but they're the first ones where you can make out surface features.

...I must say that is a weird looking space rock there. Looks like two asteroids glued together.

Smarter people then me seem to be thinking they collided at walking speed sometime in the early life of the Solar system.

I kind of wonder if this might help us understand Oumuamua's apparent weird shape. Something about being far away from a star makes these sorts of elongated shapes more feasible?

The closer to the center of orbit, the faster the orbital speed?

China has landed a spacecraft on the far side of the moon.

Hey, when Rosetta visited 67P/Churyumov Gerasimenko (67P/G-C to it's friends), the most common shape comparison was rubber ducky.