NASA study reveals Venus crust surprise | Hacker News Reader

NASA study reveals Venus crust surprise

science.nasa.gov

105 pointsmnem103 comments

- "Several upcoming missions, including NASA’s DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging)"

DAVINCI is actually cancelled in the latest budget request. For obvious reasons, the NASA press office (the OP) won't talk about this. But 50% of NASA's science funding is gone.

https://spacenews.com/white-house-proposal-would-slash-nasa-...

> But 50% of NASA's science funding is gone.

The proposed cuts to science are catastrophic, but there’s still time to call your Congressperson.

https://aas.org/posts/news/2025/05/week-of-action

I remember writing to my red congressman once and they wrote back telling me how wrong I was. Democracy felt different after that.

Supposedly, the Senate Launch System boondoggle is being killed, but not until 2027, by which time the Artemis III moon landing is supposed to happen. Since Artemis II (manned flight around the moon) has been delayed again, that's unlikely.

Ninth Space-X Starship/Super Heavy launch some time this month.

> Senate Launch System

Where can I contribute to put all the senators in a spaceship and yeet them into outer space?

I propose we just yeet one of them and see if the rest clean up their act.

Is there something to suggest that they would actually be good at their jobs if they were to be better motivated? I’m not seeing it.

They've done wilder things to stay in office

They need to be yeeted pretty far out. There is already enough garbage orbiting the Earth as it is

The ones who would have actually put the brakes on this are already trying to do that without your call. The ones who don’t care will ignore your call. Tellingly everything has fallen on party lines aside from maybe 1 or 2 republicans who realize they can deviate and save a little shame but never enough of them to affect the overall vote.

The full proposed budget is available at https://www.whitehouse.gov/wp-content/uploads/2025/05/Fiscal... folks are interested in seeing the whole picture and reasoning.

> reasoning

The justification? I don't think they are open about their reasoning.

HTTP 404

Typo in your URL. replace the last l with a d ....".pdf" not ".plf"

Thanks! Fixed.

And no thanks to autocorrect.

wp-content?

Am I the only one shocked to see wordpress here.

The WH website switched from Drupal to WordPress in 2017.

That really stinks. As I said before, the US is handing all good research and science ti China.

I would remind everyone that congress sets the budget. This is merely a proposal from the president. The proposal is regularly ignored. Nothing has been cancelled, yet, merely proposed to be cancelled.

> Scientists expected the outermost layer of Venus’ crust would grow thicker and thicker over time

I recall watching this NOVA episode in 1995 where scientists had no idea whether the lithosphere is thick or thin. Seek to 36 minutes: https://archive.org/details/VenusUnveiled/NOVA.S22E10.Venus....

I remember that episode being excellent! Scientists could tell that Venus’s crust was somehow reforming because of the crater pattern but the didn’t know whether it was gradual change or something catastrophic, and the thickness of the crust would point to one way or the other but they didn’t have that data.

> The paper used modeling to determine that its crust is about 25 miles (40 kilometers) thick on average and at most 40 miles (65 kilometers) thick.

So would that be considered “thick” or “thin”?

Thick compared to Earth, but I think it has an especially thin crust.

I'm blown away at the number of huge volcanos and relative lack of craters. If that's right, Venus must recycle its surface relatively often.

Are you just looking at the photo to determine volcanoes and craters? Wouldn't we expect that with so much atmosphere on Venus, that meteors would have a much harder time reaching the surface? That is, much larger ones would burn up or get deflected than on Earth.

Venus is a damned shame. Had planetary evolution gone just slightly differently, the solar system could have had two habitable water planets. Mars, owing to its size, was never going to cut it, but Venus might have.

I wonder how a system with 2 planets with intelligent lifeforms would've developed culturally and politically... if both civilizations grew at the same rate, 2 Galileos would've looked at the other planet and figured out "we have neighbors!", but it'd be several hundred more years before communication could be done. Even know we don't have manned missions to Mars or Venus...

> a system with 2 planets with intelligent lifeforms

That is an extremely unlikely scenario because both intelligent life forms would have had to evolve before either of them developed space flight. It took homo sapiens 4 Gyr to evolve in the first place but only 100 kyr to develop space flight after that. So the odds are slim to none.

Does intelligent life mean only human-level intelligence? If we found a bunch of chimp-like animals running around, would that count as intelligent life?

Sure, but our interactions with chimp-like intelligence on another planet are unlikely to be substantially different from our interactions with chimp-like intelligence on this planet. It only gets interesting when both are more or less evenly matched, and that is extremely unlikely.

And our interactions with same-level intelligence on another planet are unlikely to be substantially different from our interactions with same-level intelligence on this planet. We've seen this before when people from one continent encountered those from another. In fiction, we show (via projection) how we might treat other intelligent life forms (every accusation is a confession).

Spaceflight is not some law of the universe. Neither are ideas of human intelligence. Whales have bigger brains, they communicate, they have culture, they have traditions. Yet we write them off and relegate them with the rest of the animals below them and make no effort towards communication, pretending its impossible as we communicate with our dogs without thinking about it as such. We wouldn’t recognize intelligent life in the universe because we set the goalposts of intelligent life to be that of a science fiction readers expectation of what intelligent life ought to look like.

I don't know why you'd think it'd be several hundred more years before communication could be done. If they can both observe each other, then all that's left is to devise a way to signal back visually. Seeing proof of one's neighbors would definitely drive people to develop ways to communicate, though I guess both planets would need to be similarly driven in order to establish communication.

One might ask how often they have a deer or a crow attempt to make contact with them. That is the expectation for other life out there, not that they’d be exactly like ourselves but perhaps more like most other life we have observed thus far.

I based my comment on the one that said "2 planets with intelligent lifeforms would've developed culturally and politically... if both civilizations grew at the same rate, 2 Galileos would've looked at the other planet and figured out "we have neighbors!"" I think that's quite a different situation than a deer or a crow attempting to make contact. It seems likely that if scientist in the 1600s were to figure out that there's life on the other planet, they're realize that the best way they could communicate would be visually. Then it would just be a matter of devising a large enough way to signal visually.

Galileo was observing Venus in 1610; his telescope was enough to see the phases of Venus but probably not high resolution or quality enough to see someone waving Semaphore flags or lighting a bonfire. Astronauts in Low Earth Orbit can't see the Great Wall of China with the naked eye.

What scale of 'device a way to signal back visually' could done with 1600's era manufacturing and technology?

I'm basing what I said on the comment I was replying to which said that they _already_ figured out that they have neighbors. Given the level of scientific understanding in the 1600s, it seems highly likely that they'd have to have pretty definitive visual proof in order to know they have neighbors, which implies they can see at least some of what's going on over on the other planet. While you're right that they probably wouldn't be able to see someONE waving semaphore flags or lighting A bonfire, there must be a way to have multiple someones doing such in sync so that it'd be visible. Or more likely, a system of simple machines arranged in an array, with the ability to show either a white or black stretch of fabric. It probably wouldn't need to cover the entire area between machines.

I'll admit, it'd take a lot of effort/money to communicate and it'd be pretty slow, but it's not impossible to happen just decades (or perhaps even within a decade) of when its figured out that they had neighbors. Not hundreds of years.

Luckily we are up gravity well from them and also have a moon as a great source of low launch cost projectiles.

Using Hohmann transfer, I believe the energy cost is the same both ways. Of course as you point out we have the Moon, "they" have none. So we'd have plenty of rocks to throw.

That said, we'd have to throw much bigger rocks to penetrate their atmosphere. And the likely (to me) actual plans would be:

Us: launch to the Moon, set up there, launch rocks from the Moon to Venus.

Venusians: launch and travel to the asteroid belt, launch an asteroid toward Earth.

The more I think about it, the more I realize that our plan would be the same as theirs: we'd both be heading for the asteroid belt, because nothing we could reasonably launch from the Moon would put a dent in Venus with that atmosphere.

And if we assume they actually can launch through that atmosphere, we're screwed: if they can do that, they're way ahead of us.

Same energy to enter the orbit, but the kinetic energy per unit mass should be a whole lot higher at Venus than Earth, so each of your shots count for a lot more. But yeah, the main advantage is the moon. And you wouldn't launch things from the moon. You would launch pieces of the moon from mass drivers.

The situation I replied to assumed they were both inhabitable planets which I assume means Earth like atmosphere on Venus. The thick atmosphere complicates things, but I don't think you actually have to hit the ground. Tunguska didn't even get near the ground and it still leveled 1000 km^2. Also if Venus has the atmosphere there's no point of a war since there's no benefit to conquest in either direction.

If the Venusians had the technology to lob rocks, they'd have the technology to do so from the asteroid belt. They don't need to mine them their own non-existent moon.

H.G. Wells has you covered here.

Right, the biggest issue would be the unlikelihood that both planets would evolve similarly-intelligent lifeforms in the same time frames.

If Venus had a superintelligent species today, we would likely be pets or food.

If it had a superintelligent species 100,000 years ago, we will never know (or not know for quite a while).

And if it has life now that is evolving into something intelligent or superintelligent in 100,000 years, who knows if humanity will still be here to find.

Crazy factoid one: The Earth masses more than everything else between the Sun and Jupiter combined.

Crazy factoid two: Venus is 80% of the Earth's mass.

It also blows my mind that the Sun accounts for 99.86% of the entire Solar System’s mass.

Makes sense. You have a lot of gaseous outer planets, then a star who's compression needs to be so great that fusion can happen in it. That compression is going to drive up the density of the star.

"If Jupiter were a little bit bigger, we'd have a binary star system!"

I wonder if Venus could be terraformed via a sun shield placed in orbit around it. How big would it have to be to reverse the runaway greenhouse effect?

Venus probably doesn't have enough hydrogen to be of any use.

Part of the problem is having too much atmosphere. In the original Cosmos Carl Sagan talked about a hypothetical solution where we capture asteroids, and throw them at Venus in such a way that they just nick the atmosphere and knock large quantities of atmosphere out into space. One you reduce atmospheric pressure to a certain level, things could become habitable.

Then throw in iron form the atseroid belt to react with it to form carbonates. Venus is dry so brining in hydrogen form the outer planets would be necessary anyway to form wate r and thta will account for a good bit. Garden the surface so subsurface rocks which might react with the atmosphere cna absorb some. (Assumign the subsurface rocks are thta reactive.) Scoop it off with smaller versions of the same scoops used to harvets hydrogen from the gas giants.

Couldn't we just build a MegaMaid and suck the atmosphere out? If we're going to go sci-fi, it seem easier to hoover it out than capture an asteroid and nick the atmosphere just right.

Something like a solar powered space elevator that just blows atmosphere into the sun

That would require a lot of energy to ensure the gasses escape Venus' gravitational pull, which would in turn effectively be a rocket. So then we'd be adjusting to ensure we don't mess with Venus' orbit too much.

We can avoid orbital drift through the magic of building two of them.

Venus outweighs its atmosphere by about 10,000 times. This is actually less than I thought -- for comparison Earth outweighs its atmosphere by over 1,000,000 times, which is still far less than I would have guessed.

Venus's escape velocity is less than 1/3rd of its orbital velocity. According to google, Venus's orbit, despite being very circular, causes its velocity to vary by a KM/s from aphelion to perihelion.

So I believe you could send all of Venus's atmosphere off permanently into space at the cost of about 1/30,000th of Venus's orbital velocity, meaning you could very slightly circularize its orbit further.

Spinning it up would be handy.

Then, move the MegaMaid into an orbit around Mars and go from suck to blow. Venus has too much atmosphere, Mars has too little. Win Win.

It wouldn't do Mars any good. Lacking a magnetosphere, any atmosphere you add will get stripped away by the Sun.

I’ve read that a large asteroid could be positioned at a particular Mars L point and it would protect the planets atmosphere from being stripped by the sun.

I've read something similar, but I believe it has to be an asteroid with a magnetic field, whether permanent or electromagnet.

The atmosphere will be stripped away over a time period of millions of years though.

The estimate I heard is it would take 100,000 years for the atmosphere to be stripped off. That’s a long long time.

I recall one of the plans being to use the sun shield to entirely freeze out the atmosphere, then use a mass driver to chuck most of the CO2 into space. I don't recall exactly where that was supposed to be on the feasible to scifi spectrum.

I'd rather try to keep the carbon around for organic molecules. Are we sure we can't get in enough H2O and N to balance it out and build a nice thick biosphere?

You'd have to shoot it out of the solar system, otherwise much of it would reaccrete onto Venus... or onto Earth!

I guess I'll count that as another reason to prefer managing it in situ. But it might be fine, actually? Slow re-accretion can probably be managed by whatever terraforming process we've kickstarted while most of it was gone.

Oh wait, I remember the plan, ship it to Mars so they can have some decent atmospheric pressure.

Mars could use only a small fraction of it. If the entire atmosphere of Venus were moved to Mars, the surface pressure there would be 120 bars (more at the lowest point).

There’s a book where they freeze the atmosphere then cover the ice with a thick layer of dirt. But I cannot recall which.

"Venus is dry"

I thought the Venus theory was runaway greenhouse driven initially by water vapor. Going off memory, H2O is roughly 10 times as effective a greenhouse gas as CO2, with Venus being closer to the sun A larger percentage of water ended up in vapor form, leading to a feed back loop where the increased heat pushes more water to vapor leading to more heat, eventually liberating the co2 from the rock, making everything worse, ending up with the current situation where venus has way too much atmosphere.

Which is the long way to say, I think there is a lot of water on venus.

https://en.wikipedia.org/wiki/Atmosphere_of_Venus

From your link:

> Lighter gases, including water vapour, are continuously blown away by the solar wind through the induced magnetotail.

There used to be a lot of water on Venus.

Moreover, I think Venus has lost most of its hydrogen to space, so you can't even make water anymore. Hydrogen escapes the atmosphere relatively easily for Earth- and Venus-sized planets[1], and the vaporization of all the water and subsequent disassociation[2] of H2O allowed the hydrogen to escape into space.

[1] See https://en.wikipedia.org/wiki/Atmosphere#/media/File:Solar_s...

[2] See https://en.wikipedia.org/wiki/Atmospheric_escape

Earth's oxygen rich atmosphere is really important here-- any free hydrogen can readily combine with the free hydrogen, decreasing the chance of any being loss.

According to that wiki article, the hydrogen was mostly lost in the form of water vapor. The hydrogen and oxygen in the magnetotail are in almost a perfect 2:1 ratio. At least,

> Currently the main ion types being lost are O+, H+ and He+. The ratio of hydrogen to oxygen losses is around 2 (i.e. almost stoichiometric for water) indicating the ongoing loss of water.

Also Earth didn't have an oxygenated atmosphere until relatively late, a couple billion years in, so I didn't know if that could be the thing that saved it.

I don't have primary sources, unfortunately -- I'm recalling something I read in _Oxygen_, which I found reassuring. It said that, one of the benefits of our oxygen-rich atmosphere was that we would lose an insignificant amount of hydrogen/water over the next billion years. It's one of those things that doesn't actually matter to me in my daily life, but I still find comforting, so it's stuck with me.

Venus has a retrograde day that is longer than it's year.

While the atmosphere is a big problem, even without this issue the rotation would be problematic.

If the commenters are discussing diverting enough meteors to terraform Venus, there's enough fantasy to consider using nukes to apply the necessary torque to speed the orbit up

If we're spitballing, one could simply angle the impacts of asteroids to add momentum in the desired direction.

With that much atmosphere that’s a lot of tidal forces too, if you just get some I to orbit.

But the question. Is do you spin it backward or slow it down to spin it the right way, creating a situation where one side of the planet always faces the sun for a while. Might be an opportunity to freeze and cart off the other side of the atmosphere…

Why don't we simply vaporize Venus entirely and construct our own bespoke planet in its place, if it's so damn problematic

https://memory-alpha.fandom.com/wiki/Technobabble

I've read a crazy proposal:

1. "Humidify" the atmosphere by crashing comets into Venus. This will also allow us to create a temporary "cloud" around Venus that can shield it from the Sun and lower down the temperature.

2. Once the temperature is low enough, Venus will get oceans on its surface.

3. At this point, CO2 can be split into carbon and oxygen. Oxygen will be immediately bound by the huge amount of under-oxidized iron on the surface, and carbon can be buried under the new ocean. Essentially, carboniferous age for Venus.

4. Once this is done, the atmosphere will be mostly nitrogen (at ~3 bar) and people could live there with just respirators. Eventually, once the surface iron is oxidized, the atmosphere can even be made breathable.

Apparently, this can be done within 2000-5000 years without any exotic-level engineering.

How many comets would you have to crash and how would one redirect and crash them that wouldn't make this exotic-level?

Depending on a size, probably on the order of tens of thousand.

Comets in the Oort cloud take very little energy to put on a collision orbit, the Sun barely holds them gravitationally, orbital speeds in the Oort cloud are measured in _meters_ per second. So they require (relatively) little energy to put them into a required orbit. It might be doable with just regular thermonuclear charges.

It will then take these comets more than a thousand years to "fall" from the Oort cloud.

We'll be dead by then I'm afraid.

My understanding is that it was water that started the whole thing. water vapor is about ten times as effective a greenhouse gas as co2. and the runaway heat started with too much water vapor(closer to to the sun I think), leading to more heat, leading to more water vapor. eventually it got hot enough to start liberating co2 out of the rocks. leading to the current situation today where venus has way too much atmosphere.

Which is to say, putting a ring around venus to block the sun may have merit, but adding more water sounds like pouring petrol on a fire.

Water is not a driver of warming, it's an amplifier. If CO2 is removed, then the equilibrium water content will still allow Venus to be liveable.

If you're interested in human habitation of Venus overall, you may find it interesting to learn Venus is probably preferable kept at about its current temperature or only made a little colder.

See, the atmosphere at ~50 altitude... happens to be about 1 bar (which happens to be Earth's atmospheric pressure ASL)... and happens to have temperatures that can support human and plant life!

And better still, the atmosphere being mostly co2 with a little nitrogen actually means normal Earth air is a lifting gas! Starting to see where this is going?

It's not too hard to imagine the skies of Venus full of floating habitats that move to stay in the sunlight, or occasionally dock with tethers or balloons carrying cargo from extremely reinforced mining facilities deep underground (where they could be much more protected most of the time from the pressure/temperature/corrosion) -- a future where people (or machines!) might scoff at the idea of cooling off Venus and losing out on such an excellent habitation zone, one which could also fairly easily support elevated runways or launch platforms to more cheaply reach space from.

With Venus also having 91% of Earth's gravity, and those atmospheric conditions at high altitudes that add some radiation shielding and would probably let a human worker only need a very limited suit more akin to a hazmat or firefighting suit with SCBA to work outside habitats... Venus is actually easily the single best planet for humans to live on after Earth!

(Can you tell I'm writing a story set there? Hehehe)

Wow and then we get Lando

You need to give us more. I feel that just the heat is a tricky problem, even at 50km altitude. Anything todo with Venus is very much scifi at the moment. It might be easier than a moon base but we can not know.

Oh it wouldn't be easier than a moon base or simple orbital habitats. And as for Venus being scifi, anything to do with space colonization period is scifi right now; humans haven't even stepped foot on another celestial body of any kind in over half a century.

Rather my meaning was that it's (a little shockingly) the best suited planet for humans in terms of most closely and reliably resembling conditions humans could survive in, which relates to the terraforming notions I was replying to.

It'd be overwhelmingly harder to make all of Venus Earthlike than to just use the existing relatively Earthlike regions of the upper atmosphere to our advantage along with their unique properties. Cool off Venus and you just get a big ocean of liquid or frozen co2 to have to deal with after a loooong time and a lot of construction. Keep it like it is and a fraction of the resources/effort will yield far more utility while we can still enjoy a segment of the atmosphere.

Scifi? Of course!

Cool? Without a doubt!

Isaac Arthur on YouTube makes videos on sci-fi ideas that we might be able to do within the laws of physics, albeit not with today's technology. He did a video on Colonizing Venus some years ago, and an updated one a few months ago, and some others around colonisation and teraforming of the planets in the Solar System:

https://www.youtube.com/results?search_query=isaac+arthur+ve...

It actually is hard for me to imagine that. I wouldn't want to live in a floating habitat held aloft by balloons.

Maybe if I were a bird I'd be comfortable with it, but it's just disturbing. No solid ground...

Haha, i totally feel that. Maybe people will have little personal balloons for emergencies like that :p

At the same time, do consider how you already count on conventionally supported structures like bridges, buildings, tunnels, etc. not to have any defects or design flaws. Or once-in-100-years storms or earthquakes.

This magnifies further if you've ever flown on a plane or sailed on a ship. It only takes the right series of failures to be plummeting to the bottom. Now imagine people who spend months or years counting on technology and redundancy to keep them alive in space, and might expect to do so indefinitely.

Exposure therapy, baby!

All I know is if I sail on a ship and something goes wrong, I don't fall dozens of kilometers through clouds of sulphuric acid to my death.

Not on the ships I've been going on, anyway.

You won’t, but some people work for months on oil rigs in the middle of nowhere.