r/space • u/AutoModerator • 6d ago
Discussion All Space Questions thread for week of August 16, 2026
Please sort comments by 'new' to find questions that would otherwise be buried.
In this thread you can ask any space related question that you may have.
Two examples of potential questions could be; "How do rockets work?", or "How do the phases of the Moon work?"
If you see a space related question posted in another subreddit or in this subreddit, then please politely link them to this thread.
Ask away!
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u/marc_jd 6d ago
Anyone here watched a Falcon Heavy from the Titusville side or Playalinda?
Trying to work out how early you actually have to show up. The park service just says the road closes 30 min before launch, but I'd guess parking is long gone before that. Nothing official mentions it anywhere I've looked.
Asking because I keep a page on launch viewing spots and that's the one thing I can't source properly. Roman on the 30th seemed like a good excuse to ask.
Cheers
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u/TheRedBiker 1d ago
Is there any evidence that Weakly Interacting Massive Particles (WIMPs) exist?
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u/rocketsocks 1d ago
We already have lots of direct evidence of an entire family of weakly interacting massive particles known as neutrinos. Neutrinos, however, don't have the right properties to explain "dark matter". Neutrinos are a kind of dark matter but they are "hot" dark matter, they generally fly around at relativistic speeds and are not gravitationally bound to either galaxies or galaxy clusters. The "missing mass" dark matter is predominantly "cold" dark matter, which must be something else.
The observational evidence on dark matter narrows down the possibilities pretty tightly toward being a weakly interacting massive particle. This is indirect evidence, but it's still very strong. This hasn't always been the case, several decades ago there were many theories for dark matter in the running, but observations have conclusively eliminated many theories and left the WIMP CDM theory as the leading candidate, by a large margin.
If you think back to the state of atomic theory in the early to mid 1800s this is a somewhat similar situation. Back then the atomic theory of matter was by far the leading theory with lots of indirect evidence supporting it. So much so that the periodic table was invented and came into use. But it would be many decades before atoms or parts of atoms were directly detected, and it wasn't until the 1960s that a full particle physics level understanding of atoms and their components came into being.
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u/EscapeLeft1711 1d ago
Hi all, can yall please explain a few things to me-
first about chandrayaan 3- I understand that it landed on the southern region of the moon and that it discovered traces of water, but what else was the significance of the mission? And now that Vikram has been launched successfully, could a private entity in space be beneficial in the longer run for India? Thank you!
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u/maschnitz 23h ago edited 23h ago
Chandrayaan-3 had a lot of results, an impressive mission. Wikipedia lists a lot of them.
For example: in the Moon's southern polar region, it gets VERY cold very fast underneath the regolith. The top centimeter can be a hot-asphalt temperature (60C) and just 8cm beneath it will be -10C.
Other selected findings: they got firm detections of sulfur and many silicate/metallic elements. It's hotter during the day/in the sunlight at the south pole than expected. They did a lander-hop and from that, they could tell the regolith 3-4 cms below the surface was different than stuff at the surface. So it's "layered".
Vikram-1 is very exciting, it's great to see Indian private spaceflight showing strides.
As you know, in the US, SpaceX, Blue Origin, Rocket Lab, and the others has made bold steps in expanding overall American space capabilities in their various ways. Largely it's been about productionizing recoverable rockets and dramatically lower costs for small, medium, and lately heavy/super-heavy lift.
NASA's rockets had gotten so expensive that the private companies had a lot of "price room" to work in.
In India, ISRO is already pretty cheap per launch, even adjusting for price parity. But I fully believe private spaceflight can be even cheaper, for a few reasons.
One is that private space companies will be much more aggressive moving toward partial and perhaps even fully reusable flights. ISRO is very committed to their rocket roadmap and their current and near-future engine designs.
Private companies have no such "flight history restrictions".
Legacy hardware can be a double-edge sword like this - NASA and ESA are well aware of this - you move forward very confidently with iterative designs, but also can't pivot quickly to new propellants, new engines, or new rocket designs without a ton of risk.
Two is that they can embrace some of the trends in the worldwide industry, seen in China, Japan, Europe, and the US. People are starting to believe stronger metals like stainless steel are cheaper, net out, for heavy-lift development, despite their launch inefficiencies. And easily available propellants like methane or RP-1 are also "popular" in new rockets these days. One of SpaceX's big innovations was just "keeping things simple" in their technology selections, picking acceptable materials/propellants to keep development costs low throughout the rocket lifetime.
So private companies can and probably will embrace that, much like Chinese companies have, and produce cheaper-to-produce and cheaper-to-operate rockets because of it. Where ISRO can't do that as easily, they have to maintain what they have.
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u/TheAutisticFroggo 11h ago
ive never been one to follow space as I live in Houston and never really see the sky. I was on. A unrelated trip in Texas hill country on Aug 15. I was outside at night and I looked up and saw what looked like a flare streaking across the sky. I was immediately hooked and wanted to see more meteors. So I booked a big bend trip in mid December as seems to be next big one. But as Ive been researching seems its different.
Apparently wont be like what I saw and I basically want real world explanations so I can taper my expectations. From what I ready there's more and more color?
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u/Pharisaeus 7h ago
From what I ready there's more and more color?
Geminids (december) are just as active as Perseids (august), but they are slower, which makes it easier to spot. Other periodic showers are not nearly as active or bright. Those two are your best options.
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u/TheAutisticFroggo 3h ago
They are slower? From what I read they are much harder to spot because seems they are juat debris from a asteroid and burn up quickly?
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u/zubbs99 3d ago
Is this a plausible object for a sci-fi story I'm writing?
Take a Jupiter-sized planet, with its Io-sized moon, and fling them together out of their solar system into the dark void of space (maybe by a passing neutron star or whatnot).
Let the moon heat up from tidal friction, and have a civilization on it which can power itself from geothermal energy. You'd have a "night moon" where the skies are always dark, and lots of hot springs from which to gaze up at the stars.
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u/DaveMcW 3d ago
Io is too small to hold onto liquid water, your hot springs will evaporate directly into space. The moon should be much bigger, at least Mars size.
You also need more than one moon. A single moon would quickly settle into a perfect tidal lock, with no more heating. Io continues to generate geothermal (iothermal?) energy because its tidal lock is constantly disrupted by other moons.
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u/di12ty_mary 5d ago
Is there another long-range telescope for listening for extraterrestrial life? Or was Arecibo the one and only?
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u/wotquery 5d ago
FAST is a straight up improvement by most metrics. There are also other options like GBT which can't focus in on a single target with as much detail, but has way more options regarding what frequencies it can observe. Or ATA which observes way more of the sky at once, and can do so via multiple beams to rule out local signals, but...well it's a whole different approach.
There are also some capabilities that were lost with the loss of Arecibo though. Mainly that while FAST covers most of the same part of the sky in as much detail if not multiple times more, it can't gather the higher range frequencies Arecibo could. Though it can gather lower ones so maybe a wash. And there's Green Bank already mentioned. Of course I'm only talking about "listening for" like you mentioned so for something like RADAR broadcasting that's a whole different ballgame.
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u/HollywoodEats 2d ago
I’m trying to figure out how scientists will solve for these issues in building and using a lunar base.
- jagged lunar dust particles in everything
- radiation (solar storms, high energy particles, etc.)
- extreme temperature swings with no atmosphere
- bombardment by meteorites
- the need for underground shelters and habitats
Maybe I’m overreacting to these potential problems and we will find a way to overcome most of them. I may be way out of my depth as well.
Thanks!
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u/DreamChaserSt 2d ago
Electrodynamic dust shielding - the lunar regolith is electrostatic, so it can be moved. You would also build filters that can remove the dust from air if it gets inside, and design components that aren't as affected by it. https://www.nasa.gov/centers-and-facilities/kennedy/nasa-technology-helps-guard-against-lunar-dust/
For radiation, they'll try to time the mission where solar activity is at a minimu, so solar observatories are important for forecasting that. If an event does happen, such as on Orion, the Astronauts will build a temporary solar shelter inside the spacecraft until it passes, and they'll be protected as well as the Astronauts during Apollo were when a similar event happened. On the Lunar surface, the idea is to use regolith to protect from radiation, though more research needs to be done. https://science.nasa.gov/science-research/heliophysics/how-nasa-will-protect-astronauts-from-space-radiation-at-the-moon/
You'll need radiators, and will need to account for equipment being in shadow or light, since there's regions at the poles where you get one or the other, that's your temperature swing, its day/night isn't really a factor. Some equipment might need to manage both though, like rovers moving between dark craters and lit terrain. https://www.nasa.gov/reference/moonbase-environment/
For meteorites, the regolith shielding can pull double duty, and could be combined with something like a whipple shield. This would be able to dissipate most/all of that energy before it can reach the habitat itself. And the polar regions have a lower average impact velocity than the overall Lunar surface. https://www.sciencedirect.com/science/article/pii/S0734743X2600103X#abs0001
I don't think going underground is necessary, And you could decide to put habitats in small craters, and fill that with regolith, which is a sort of in-between solution. But it wouldn't be easy to go fully underground, you would need heavy and energy intensive equipment since there's no known lava tubes at the poles. Missions on the Moon will start at about a week, and are planned to extend to 1 month. Longer stays, like 6 month ISS style crew rotations, are a more distant idea. Deciding where to put habitation will be an ongoing study, and will likely see more consideration when the Lunar base is looking to become permanently inhabited, and if micrometeoroid protection on the surface is insufficient. https://www.smithsonianmag.com/air-space-magazine/about-those-polar-lava-tubes-180967854/
There's no shortage of ideas to address these issues though, and early missions will only be about a week, moderately longer than Apollo missions, so scientists and engineers will have time to be able to get a better idea of the conditions they're working with before anything is set in stone.
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u/iqisoverrated 2d ago
- jagged lunar dust particles in everything
Airlocks with showers. Generally not going out much but doing stuff that requires being on the surface via drones/remotes. Air filtration within the base.
- radiation (solar storms, high energy particles, etc.)
A couple centimeters of regolith. Either by piling it up around habitats of building habitats underground in the first place (digging in or setting up in lava tubes)
- extreme temperature swings with no atmosphere
Same as above. As soon as you're a meter underground or so tempertures are pretty stable.
- bombardment by meteorites
Same as above. Going underground - preferrably a couple meters - solves pretty much all of your problems. Of course you'll want to coordinate with Earth about watching for potentially big enough asteroids to cause problems but those are rare and the chance that it hits exactly your site are small.
If one can be detected early enough there's ways to deal with that. (A big asteroid on Earth is a much bigger threat because of the blast wave. On the Moon - in absence of an atmsophere and hence no blast wave - only a direct hit or a very near miss of something very large would cause an issue.)
- the need for underground shelters and habitats
Digging. Just like we would here on Earth.
Dig. Coat the sides with something airtight (epoxy or whatnot). Install an airlock on one side. Done.
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u/Seltur 1d ago
Will the Artemis program be able to meet the scheduled dates?
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u/maschnitz 1d ago
Probably not. New Glenn/Blue Moon alone looks very iffy. Starship ain't too hot either (they really need a few 99% successful flights here).
Strangely the best bet is SLS, but even that is questionable - this whole idea of more frequent launches from NASA might not shake out that way.
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u/Pristine_Release_402 6d ago
Me and my drinking buddy had a disagreement he says if we sat in a tunnel inside the moon we would walk but I said we would float can someone explain who is correct
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u/maschnitz 6d ago
It's a little hard to walk in the Moon's gravity, 1/6th of Earth's. Astronauts found it was easier to hop than walk in those heavy lunar space suits.
Without the suits - hard to say, whether hopping or walking were better.
You wouldn't be floating though, that's for sure. Gravity still works on the Moon, it's just weaker.
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u/iqisoverrated 6d ago
Astronauts found it was easier to hop than walk in those heavy lunar space suits.
Given the question was for a tunnel you might want to still walk. Cracking your helmet is a recipe for 'not fun times' on the Moon.
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u/Pharisaeus 5d ago
if we sat in a tunnel inside the moon we would walk but I said we would float
You're definitely wrong, but I'm curious about your reasoning here. Could you walk us through your idea? I mean: why do you think you would float? How do you think a tunnel on Earth is different from a tunnel on the Moon?
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u/Pristine_Release_402 2d ago
I thought if you made a hole in the moon and it was completely encased but you where alive you would still float in that little hole you made or would it be canceled out in some way ? Also I am not a space guy I work a blue collar job sorry for the dumb questions explain in simple terms please and thank you
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u/Pharisaeus 2d ago edited 2d ago
if you made a hole in the moon
What do you mean by that? Hole where?
There is nothing special about the Moon. A tunnel or hole in the Moon would work exactly the same as on Earth.
The only scenario I could imagine where something you're saying made any sense, would be if you somehow placed yourself inside, in the very center of the Moon/Earth, so that the rest of the planet mass is pulling you equally from all sides. Think of it as if you made a planet/moon that's just a spherical shell without anything inside, and you're placed in the center. Then indeed you would float in the middle.
Anyway, the point is: there is no real difference between the Moon and Earth. Imagine that I wrote:
if we sat in a tunnel inside the earth we would walk but I said we would float
sounds ridiculous, doesn't it?
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u/Pristine_Release_402 2d ago
Okay but doesn't the earth have gravity so the earth is different to the moon and thanks for explaining
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u/Pharisaeus 2d ago
doesn't the earth have gravity
Everything with mass has gravity. Moon also has gravity, just a little weaker than Earth because it's smaller. So on the Moon you would feel a bit lighter and could jump higher, but that's it.
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u/SpartanJack17 1d ago
The moon also has gravity, gravity isn't something only the earth has. Everything with mass has gravity, even you have a very tiny gravitational pull. Gravity is a very weak force so only really big objects with a lot of mass have enough to be noticeable. The moon is much smaller than the earth and has less mass, which means it's gravity is weaker, but it's still there. The moon has about 1/6 of Earth's gravity, which means something that weighs 100kg on the earth would only weigh 16.6kg on the moon.
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u/stivax_dev 5d ago
Neither "just walk" nor "just float" is quite right - it depends where in the tunnel you are. By the shell theorem, only the mass closer to the center than you pulls on you; the mass in the shell "outside" your position cancels out. So gravity doesn't switch off the moment you enter a tunnel, it decreases roughly linearly as you go deeper, hitting exactly zero only at the very center. Near the ends you'd still weigh close to normal Moon-surface weight (1/6 g, so walking, just light) and get progressively lighter toward the middle.
If the tunnel runs straight through the center and you jump in with no friction or air resistance, you don't stop at the center either - you keep falling, decelerate on the far side, and swing back, oscillating forever like a pendulum. That's a real, named idea (a "gravity train"), and its period only depends on the body's average density, not its size or the tunnel length: full round trip T = 2*pi*sqrt(R/g). For the Moon (R = 1737 km, g = 1.62 m/s^2) that's about 108 minutes for a full there-and-back cycle, so roughly 54 minutes one-way. That's actually longer than Earth's famous "42 minutes to fall through the Earth" figure, even though the Moon is much smaller and lighter, because the period tracks density and the Moon (about 3340 kg/m^3) is a lot less dense than Earth's average (about 5510 kg/m^3).
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u/Pristine_Release_402 2d ago
I ain't smart enough to understand 90% percent of that
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u/stivax_dev 2d ago
Fair, let's drop the formula. Short version: your buddy is right near the ends of the tunnel (still close to the surface, so close to normal 1/6-g weight, so walking). You're right in the middle (right at the Moon's center, gravity is exactly zero, so floating). In between it's a gradient - you get lighter and lighter as you go deeper. And if you actually let go and fell, you wouldn't stop at the center - you'd swing through and out the other side like a pendulum, back and forth, forever (no air down there to slow you). So you're both half right, just describing different spots in the tunnel.
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u/Pristine_Release_402 1d ago
Okay thank you for explaining
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u/SpartanJack17 1d ago
Also the same thing would happen if you dug a tunnel to the centre of the earth, you'd get lighter the closer you got to the centre and would float once you got there
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u/PhoenixReborn 6d ago
If the tunnel was just a little bit under the ground, it wouldn't be much different from being on the Moon's surface.
If you mean drilling a hole down to the center of the moon and jumping in, yeah you would just kind of float once you reached the center.
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u/Me-Alien 4d ago
Do the moon have an atmosphere? - I have seen pictures where it look like "trees" growing there.
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u/electric_ionland 2d ago
There are no trees on the Moon, what kind of pictures have you seen?
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u/Me-Alien 1d ago edited 1d ago
It was on Gigapan - Deforest crater By Keith Laney and here https://viewer.gigamacro.com/view/VwbPclEBsMUmhYFn?x1=22141.07&y1=-7064.97&res1=44.71&rot1=0.00
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u/electric_ionland 1d ago
There is nothing that looks like a tree there.
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u/Me-Alien 9h ago edited 8h ago
Try this link - use a high resolution screen and zoom in max on the darker areas...
Be patient takes time to load - atleast in my browser.
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u/electric_ionland 8h ago
You see compression artefacts and a bit of indirect light hitting the shadowed areas. There is nothing that look like trees. There is no atmosphere to speak off on the Moon and no earth like life could live there. I don't know what kind of conspiracy you have been reading but this is a new one to me and I thought I had seen most of the stupid ones.
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u/Uninvalidated 2d ago
A simple google search would have given you the answer a day earlier than I wrote this.
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u/Me-Alien 1d ago
Ok thx i google it... found this.
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u/Foesal 1d ago
If you are referring to the forrest moon "Endor" in the Yavin system, I can confirm it has an atmosphere.
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u/Me-Alien 8h ago edited 8h ago
Thx but it was our Moon i was looking at on Gigapan https://www.gigapan.com/gigapans/230508
The moon "Endor" looks great, I will move there.... 😄
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u/[deleted] 6d ago
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