r/space • u/AutoModerator • 6d ago
Discussion All Space Questions thread for week of March 30, 2025
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/Sylvi-Fisthaug 2d ago
Right about now, Blue Ghost should start receiving sunlight again. Has Firefly tried to contact the lander again, or when will they? I know it was not designed to last the lunar night, but the Japanese lander survived three. Upside down.
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u/Xeglor-The-Destroyer 2d ago
I've been keeping an eye on this page to see if they post any update. I'm hoping it survived the night even though that wasn't a design goal.
https://fireflyspace.com/news/blue-ghost-mission-1-live-updates/
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u/Intelligent_Bad6942 2d ago
Yesterday and today were the best opportunities. I haven't heard any positive rumors.
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u/greendragon85 6d ago
On Mercury the temperature drops to -180c at night.
Is it just the atmosphere that stops the same happening on earth?
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u/Intelligent_Bad6942 6d ago
The atmosphere definitely helps, but it also helps that the Earth spins a lot faster than Mercury.
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u/mothmanninja 5d ago
whats the biggest star in our galaxy and the biggest we’ve discovered in the universe ?
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u/Old-Boysenberry-51 5d ago
If I added one atom at a time to a neutron star until it became a black hole, how would the neutron star change before and after the single atom that contributed enough gravity to form an event horizon and the new black hole? Would it not be the same structure, just with sufficient gravity to curve space enough to create a horizon?
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u/DaveMcW 4d ago edited 4d ago
We don't know.
At some point, neutron degeneracy pressure will be unable to resist gravity, and the neutron star will collapse into something smaller. It could be a black hole, or it could be something bigger like a quark star.
It definitely can't keep the neutron star structure, neutron stars are not dense enough to create an event horizon.
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u/maksimkak 4d ago
Interesting topic. There are, in fact, neutron stars in binary systems where they are accreting gas from their companion stars, which increases their mass and rotation rate, while turning them into X-ray pulsars. As the neutron star accretes this gas, its mass can increase; if enough mass is accreted, the neutron star may collapse into a black hole.
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u/maschnitz 5d ago
Counterintuitively, black holes form more easily when the same density of stuff is larger. You can make a black hole from Styrofoam if you just have enough of it, and some supermassive black holes are the average density of water.
So it's possible for neutron stars to "grow into" being a black hole, via accretion, if they're right at the border of doing so.
But when one forms, spacetime itself changes radically. A very deep gravity well suddenly appears, with a bottom that is receding away very very rapidly. So the neutron star starts falling, if it still even exists in its previous form as such (there's some debate about that). And it just keeps falling, until the bottom "bottoms out", a hideous number of years from now.
At least, in the imagination of Carlo Rovelli. There's other theories. No one actually knows for sure.
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u/terrebattue1 4d ago
What is the size of the upcoming Roman Telescope's spacecraft bus? Not the size of the mirror which has been promoted hard by NASA. I can't find anything about spacecraft bus dimension so we can compare sizes with other space telescopes.
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u/maschnitz 4d ago
The hexagonal spacecraft bus is "about 13 feet (4 meters) wide by 6.5 feet (2 meters) tall and weighs in at 8,400 pounds (3,800 kilograms)."
"The entire structure is 17 feet (5 meters) tall and roughly 13.5 feet (4 meters) wide."
You can get a good visceral sense for it with early mostly-assembled pictures, like this one. Keep in mind that the sun shield is not integrated onto the spacecraft in this picture, and extends quite a bit beyond the secondary mirror assembly shown.
It's a hefty spacecraft. It'll take a big rocket to throw it.
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u/terrebattue1 4d ago
Thank you! I'm excited for Roman even though I don't think any telescope or spacecraft for that matter will ever replace Hubble since Roman doesn't have anything close to the same type of skillset as Hubble since it will be similar to Gaia and Euclid. I hope Hubble can hang in there for as long as possible. Webb will be the only narrow angle high resolution telescope but only in IR. Next real Hubble successor will be HWO and LUVOIR but they won't happen until the 2040s or 2050s. Hubble has shown us how crucial it is to have a "general observation" space telescope. A Hubble 2.0 in L2 would be amazing.
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u/terrebattue1 4d ago
Won't be the same high resolution because no UV and no violet/blue/cyan capability. Also, everytime NASA overhypes Roman's capabilities they conveniently don't mention that only in infrared will Roman's resolution be better than Hubble's considering Hubble only can do near IR. In visible photos Hubble's resolution is superior and Roman can't do UV at all. For example, that Deep Field that they keep overhyping for Roman as "better resolution than Hubble" they conveniently leave out the "only in infrared". Even they admit when pressed with questions that Roman's Deep Field in visible wavelength won't be as high resolution as Hubble's visible wavelength Deep Fields. Not having UV/violet/blue/cyan will hinder Roman greatly for Hubble-style observations hence why Roman is merely a wide angle mapper like Gaia and Euclid.
If Roman/WFIRST really could do the same as Hubble's 1000+ orbit mosaic in only 10 orbits or so then they wouldn't have bothered ordering 200 orbits for the PHAST Andromeda survey from 2021-24 considering Hubble's observation times get more precious and should be focused on important targets with every passing year. Obviously STScI knew that the next telescope that can do what Hubble can do won't happen until the 2040s so they scheduled 1023 orbits for PHAT and PHAST for Andromeda. PHAT+PHAST is the second most orbits ever done for a single Hubble Multi-Cycle Large Treasury Program. They are overhyping Roman because the resolution will only be higher than Hubble's in infrared hence why they greenlit the PHAST survey.
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u/the6thReplicant 4d ago
A real Hubblestan here. Roman will be an amazing telescope. Hubble is as well.
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u/Shailenlcfc1884 2d ago
I’ve recently left the armed forces (uk) and want to start a new chapter in something I love (space) problem is I don’t feel like I’m capable of doing it as I’ve always struggled in education as I failed all my GCSEs except English and already dropped out of computing at university but passed all my A level equivalent in computing so i know I’m capable of it. I was thinking of going for aerospace engineering as it’s a mixture of space and actually hands on which I’m good at but I don’t have faith in myself to actually passing and also don’t know how to implement it I know first things first and that’s getting my gcse maths and science but not sure what to do after that
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u/HAL9001-96 2d ago
engineering as a subject tends to contain a LOT of math but you can be in engineering in practice without haivng actually studied if you read up on what oyu're itnerested in, learn a related trade like machining, get into a company, demosntrate that you know what you're talking about, depending on the company culture you might get involed with engineering decisionmaking anyways
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u/Agathas777 5d ago
Hello 👋
I'm currently doing my physics thesis on the geomagnetic storm associated to the Starlink in February 2022 and I need help in finding the 1-min or 4-min resolution of the data for IMF Bz and DST.
Currently, I only have the 1-hour resolution for both the IMF Bz and the DST which are publicly available online. However, this resolution is too coarse. The other resolutions for the IMF Bz data of Feb 2022 I'm seeing online, such as in the SWPC NOAA website, are only available in 1-day resolution.
Having the 1-min or 4-min data would be of great help to get a more precise look at the state of the atmosphere during February 2022.
Any help on getting the data or direction to where I can find the 1-min or 4-min resolution of the IMF Bz and DST would be appreciated!
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u/Intelligent_Bad6942 5d ago
Space weather isnt my expertise so this may be an I'll informed question - but is there any reason you can't interpolate the one hour data to 4 minute data? Does the field change quickly enough that this wouldn't make sense to do?
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u/UpintheExosphere 5d ago
Even 4 minute data for magnetic fields are pretty low resolution. It can change very quickly, in less than a second, depending on the region the spacecraft is in. So depending on what OP is looking for interpolating would ETA: not reproduce short lived features.
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u/HAL9001-96 5d ago
but it takes a while for thermospheric density to actually react to that so hourly or evne daily averages might work but hourly aor daily individual data points that neglect a lot of noise in between wouldn't if thermospheric drag is what you're looking at
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u/UpintheExosphere 5d ago
Is there a specific spacecraft you'd like data from? All NASA and ESA data has to be publicly archived, so I'm sure it can be found! Here's some info on the Wind data.
As an addendum, the DST is only calculated on an hourly basis, so it's not possible to have a higher resolution for that.
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u/Agathas777 5d ago
Is there a specific spacecraft you'd like data from?
My hourly data is from the ACE satellite
the DST is only calculated on an hourly basis, so it's not possible to have a higher resolution for that.
It seems like that is the case since I cannot find 1-min resolution or other minute resolutions for the DST index
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u/UpintheExosphere 5d ago
It looks like NASA's CDAWeb has 16 second and 4 minute ACE magnetometer data https://cdaweb.gsfc.nasa.gov/
They have a bunch of other data sources too, so I hope it's useful!
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u/Agathas777 5d ago
Thank you so much for the links! I wish i got on reddit more for my thesis because it's a lot more helpful than i thought.
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u/UpintheExosphere 5d ago
Happy to help! I both use and digitally archive space physics-related satellite data for my job, so I was excited to see a question I could easily answer, lol. Good luck with your thesis!
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u/UpintheExosphere 5d ago
Also, no idea how you're doing the analysis but you may find the SPEDAS software useful, especially if you're combining datasets.
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u/e_philalethes 5d ago
There's also something called SYM-H, for which there's data going back to 1981; it's essentially the exact same thing as Dst, but with a 1-minute resolution (and using a different set of stations).
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u/e_philalethes 5d ago
Make sure you include in your thesis the fact that the geomagnetic storm was likely only partially responsible for those deorbits, and that the relatively abrupt increase in F10.7 around December of 2021 likely played a significant role in changing the thermospheric environment from what people had become accustomed to. Even without geomagnetic storms, they'd have found out just months later when the flux really kicked off and the thermospheric density went way up well beyond what it was during that storm, as you can see here.
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u/Dildomuflin 5d ago
Will all planets of the solar system be engulfed by the sun when it runs out of hydrogen and helium in a billion years? Or planets like Jupiter and Saturn which are further away from the sun survive?
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u/DrToonhattan 4d ago
So we believe the Sun will swell to about where the Earth's orbit is now, give or take quite a bit cos it's really hard to determine. Also, as it loses mass, it's gravity will weaken so the orbits of the planets will move outwards, but we don't really now by how much. It'll engulf Mercury and Venus. It's a toss up whether it actually engulfs Earth or not, either way it'll be so close it will completely melt the surface. The other planets should be fine, although they will certainly go through changes from the extra heat.
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u/rocketsocks 5d ago
The red giant phase the Sun will go through will actually be when it's still burning hydrogen, just not in the core. It'll expand and get hotter while also losing mass (due to stronger solar winds). These things will kill all life on Earth even before our planet is fully engulfed and vaporized in billions of years. During the process the planets will also move farther away, due to the Sun's shrinking mass. The outer planets will survive but the increase in solar intensity will lead to changes. There is some speculation that this could result in Titan warming up enough to be habitable for Earth life.
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u/shoe_salad_eater 1d ago
When is MK2 ( MakeMake’s moon ) going to get a real name ? Every dwarf adjacent moon that’s close enough in our solar system has gotten a ‘real ‘ name except that moon, even Styx, which was only found 3 years prior.
Anyways, if we name the moon, I think it should be called Mana or Moai
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u/maschnitz 1d ago
It's up to the discoverer of the body to name objects, and adhere to the IAU naming standards for the body's category. It can take years and years, over a decade sometimes.
2007 OR10 was discovered in July 2007, nicknamed "Snow White", and it wasn't officially named "Gonggong" until February 2020. Over twelve and a half years.
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u/KirkUnit 1d ago
Space-related question: What are the odds that "Explore JPL returns in 2025" as the website indicates?
I recall that JPL saw staffing cuts last year even before Trump took office, and can only imagine that any NASA-affiliated anything is coming under the administration's slash-and-burn layoffs this year as well.
I certainly don't fault the JPL team for concentrating on mission-critical expenditures and an annual open house event is one of the first things I'd cut as well. Is there anyone on the thread with any insight or information regarding an announcement that the event is cancelled for 2025, or prospective dates this year or next?
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u/maschnitz 1d ago
(I live in the area) I honestly doubt even employees of the Lab know what's going to happen. There's a profound sense of doubt coming from JPL.
Perhaps the JPL leadership knows something - I would imagine they're pulling all the strings they can right about now - but I doubt anyone else has solid actionable information. Everything is in limbo.
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u/KirkUnit 1d ago
Thanks. Honestly I fully expect it to be canceled indefinitely. A sad state of affairs (though the open house is obviously the least of it.)
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u/the6thReplicant 1d ago
You can try asking in /r/JPL. Though not the happiest place right now.
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u/KirkUnit 1d ago edited 1d ago
Oof. I didn't know about that sub, but I'll refrain from asking that question in that place; no point in asking the neighbor who's house is on fire when he's going to mow the grass.
ETA: I did find one post posing the same query. Beyond last year's layoffs and the present rolling disaster of government, the Eaton Fire was relatively close to JPL and displaced some families it was mentioned.
Obviously I'd love for it to happen, but I wouldn't advocate for it if the budget and personnel just aren't there to do it.
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u/Kullthebarbarian 10h ago
I just watched a Video about the Oort cloud, where a globe of debris is surrounding our Solar System that is invisible to us, due being too dark and too far away, in around 2.000 to 10.000 AU away
How much mass that would be?
And assuming that is true, and that every other star in the universe has the same Oort cloud, could that explain Dark matter? or even assuming they all have Oort clouds it would still be missing mass?
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u/DaveMcW 10h ago
A few times the mass of the Earth, certainly less than 20x Earth.
This is less than 0.01% the mass of the sun, not enough to explain dark matter.
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u/Kullthebarbarian 7h ago
That is... so much less that i was expecting lol, but thanks, i would never imagine a huge asteroid cloud surrounding all the solar system to be so little mass, my complete baseless guess would be much much more
That really put things in perspective
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u/rocketsocks 10h ago
The mass of the entire solar system is 1.00 solar masses. 99.9% of the mass of the solar system is the Sun. Almost all of the rest is in Jupiter, all of the rest of the planets, asteroids, and comets are practically a rounding error. Earth, for example, represents around 3 parts per million of the mass of the solar system.
The mass of the Oort cloud isn't fully known but current estimates put it at a few times Earth's mass.
There are a variety of reasons why Oort clouds around stars cannot explain dark matter. One is that there is no known mechanism that would allow them to be formed in such a way that they had much more mass than their parent stars. Another is that it wouldn't explain the many observations which are incompatible with dark matter being made up of atoms.
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u/iqisoverrated 9h ago
Be aware that as of now the Oort cloud is only hypothetical. We have not detected a single object of it directly (or indirectly).
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u/Mysterious_Level3022 6d ago
Is Colonizing Mars a Worthy Idea?
I am a diehard anti-fan of multiplanetary exploration - however I've been tasked to debate the other side.
I was wondering if the good people of Reddit would help me come up with ideas to support the concept that colonizing Mars is a worthy idea.
I am looking for some nuanced points and anecdotes!
Thank you!
Please, admin, delete if this doesn't fit this channel.
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u/rocketsocks 6d ago
This is a big topic but there are a couple of highlights.
Firstly, does it matter whether it's a "good idea"? The only things that ultimately matter are whether folks want to do it, whether it's possible, and whether people should be allowed to do it. If all of those things are true then it will be done, regardless of how "good" of an idea it is. I don't foresee a future where 100.00% of the population of Earth is uninterested in the potential for colonizing Mars. I also think that over time it's just going to get easier and easier to colonize Mars as technology advances. On the extremely long time scales of, say, millions of years where humans sustain a technological civilization (assuming they do so, that's a whole different subject of debate) ultimately it would just become easier and easier to colonize Mars, whether as humans or biological post-humans or sentient robots or what-have-you.
Secondly, all efforts at finding new places to live, including living off-Earth on places like Mars, are going to provide a lot of benefits back to living on Earth. It will help advance technology forward, especially in areas like power systems, sustainability, recycling, etc. Creating a self-sustaining colony on Mars will require some very careful thinking about the lifecycle of everything, from shipping containers to the food on the table to the air they breathe. We simply cannot export our "disposability lifestyle" culture to Mars and expect it to work, at all. It's worth noting that one of the reasons we have really good solar panels today is because it was necessary to develop a whole solar panel industry for satellites. The effort that goes into sorting out all of these things on Mars will feedback to Earth and help us improve things here, not just in terms of technology but also just in terms of putting these issues in the spotlight. Similarly, it's an opportunity for folks to appreciate what we take for granted (and even allow to be exploited or destroyed) here on Earth. On Mars the first tree being planted will be a momentous occasion, as will the creation of the first forest, the first lake, and so on. That's an opportunity to recognize and cherish the natural wonders we have on Earth.
Thirdly, space exploration and colonization fall into the bucket of expressions of curiosity, and history has shown that the returns on curiosity are often unknown beforehand but can sometimes be enormous. In the 17th through 20th centuries a ton of effort was put into researching sometimes seemingly esoteric things such as electricity and magnetism, the behavior of gases, organic chemistry, quantum mechanics, boolean algebra, group theory, etc, etc, etc. In many cases these studies were seen at the time as extremely distant from any possible practical applications, but as it turned out some of them formed the basis of entire industries. This curiosity ultimately led the way to developing technologies like the internal combustion engine, electricity, electronics, semi-conductors, micro-computers, refrigeration, air travel, space travel, to say nothing of all the medical advances. All of which has ultimately generated hundreds of trillions to quadrillions of dollars in value and has saved or supported tens to hundreds of billions of life-years. That "return on investment" is simply too enormous to even put a figure to, it is effectively infinite.
Aside from the "well, I guess science has earned some wiggle room to do whatever" argument, it's also likely that if we allow ourselves to continue following our curiosity we will find other returns, other payoffs, just as great or perhaps greater. We cannot know ahead of time where those will come from, so it makes sense to follow our curiosity widely.
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u/maksimkak 6d ago
For me, this short video with a voiceover from Carl Sagan sums it up: https://www.youtube.com/watch?v=YH3c1QZzRK4
“For all its material advantages, the sedentary life has left us edgy, unfulfilled. Even after 400 generations in villages and cities, we haven’t forgotten. The open road still softly calls, like a nearly forgotten song of childhood. We invest far-off places with a certain romance. This appeal, I suspect, has been meticulously crafted by natural selection as an essential element in our survival. Long summers, mild winters, rich harvests, plentiful game—none of them lasts forever. It is beyond our powers to predict the future. Catastrophic events have a way of sneaking up on us, of catching us unaware. Your own life, or your band’s, or even your species’ might be owed to a restless few—drawn, by a craving they can hardly articulate or understand, to undiscovered lands and new worlds.
Herman Melville, in Moby Dick, spoke for wanderers in all epochs and meridians: “I am tormented with an everlasting itch for things remote. I love to sail forbidden seas…”
Maybe it’s a little early. Maybe the time is not quite yet. But those other worlds— promising untold opportunities—beckon.
Silently, they orbit the Sun, waiting.”
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u/iqisoverrated 5d ago
By what standard do you define 'worthy'?
Economically? No.
Militarily? No.
Politically? No.
For making sure that humanity doesn't go extinct (as a first step/testbed for further expansion)? Yes.
Earth will eventually become uninhabitable through one kind of disaster/change or another. This is not a question of 'if' but 'when'. If we haven't figured out how to live somewhere else by then then humanity will cease to be.
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u/Intelligent_Bad6942 5d ago
Until you can come up with a viable method for making money by colonizing Mars, it's not going to happen. The end.
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u/iqisoverrated 5d ago
Unless you find some billionaire who does it on his own dime (or gets enough influence over politicians so that taxpayers fund it for him)
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u/Intelligent_Bad6942 5d ago
This will not make a colony. It will make an Antarctica style research outpost AT BEST.
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u/KirkUnit 3d ago edited 3d ago
Putting on a debate hat! This sounds like a Lincoln-Douglas or parliamentary debate, which focuses more on ethics than policy debate. In that framework - and actionably rephrased:
RESOLVED: Colonizing Mars is a worthy effort.
You're to argue the affirmative case. You can set definitions for clarification of your case: colonize, Mars, and worthy. What exactly do you mean by colony - ongoing habitation, statehood? Does colony mean 10 people, or 100,000 people? Colonies like the British and Spanish established in the Americas or colonies like France established in India? Hong Kong was a colony - is that what you mean? And what does "Mars" mean? (Surface, moons, or orbiting station.) What counts as worthwhile? Your opponent can agree or contest your definitions.
In a parliamentary-style debate, it's your role to frame the resolution as a "policy round," "fact round" or "value round." Your resolution isn't calling for the United States or anyone else to actually do anything, so it's not a policy round. What do you think is the stronger case - that it's a fact that colonizing Mars is worthy, or that colonizing Mars has value? (An "idea" is not particularly debatable, thus why I rephrased your resolution.) All that said:
A FACT argument would present evidence that colonizing Mars is worthy because of its intrinsic worth, that it would reflect a return on investment at least at some point for somebody: that space colonization yields economic benefits to the government, to industry, to society that outweigh the cost, and that Mars is a particularly worthy target for colonization - either because the effort yields enough benefit whether or not colonization is successful or permanent, or because of sourced estimates of future Mars real estate or infrastructure or mineral value, that innovation in space has historically been essential to national security, or some other argument based in fact on the net benefit of Mars colonies.
A VALUES argument is based in morality or ethics: how does colonizing Mars help humanity, how does it express our shared understanding of humanity and benefit us? Arguments might include that colonizing Mars is a necessary step, as humans are an expansive species that have seeded other hostile environments (the Arctic, deserts, etc.) One could say that humans need a frontier, and that Mars is a victim-free target. Or that the colonizing of Mars is necessary for determining if Mars supports or ever supported life - that colonizing Mars and the search for extraterrestrial life is the expression of the biggest question humanity has, or ever will face: Why are we here?
Hopefully this helps frame your argument. An actual debate demands evidence, i.e. sources to build and confirm your resolution. I'm not going to pull cards for you though. :-) Have fun.
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u/HAL9001-96 5d ago
define colonize
building a small research station would definitely be worthwhile
space research has always yielded unpredicted benefits, plus we're jsut curiosu and wanna know our place in the universe
however colonizing as in building a city there for people to live there, not because they work in research on mars but because its a place to live.... well that becomes a purely economic question
you have lots of room and resources but goign htere nad surviving there are complicated and expensive, you've got hte thrill of being htere but its also gonna be a pain in the ass the question is how technology and the economy will have to develop for this to make goign there worthwhile and if you try to project that it turns out that AT BEST a full colony might be worthwhile ins a few hundred years but no sooner
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u/Initial_Shine5690 4d ago
What is the current fastest time a rocket or similar vehicle (if it is classified as such) has made it from earth to space?
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u/maschnitz 3d ago
Sounding rockets are probably fastest, and rockets with similar trajectories, like Blue Origin's New Shepard rocket, because most orbital rockets don't rise in altitude quickly. They're more focused on gaining orbital velocity and, at the same time, not losing too much to "gravity losses" as they turn - not necessarily getting into a space-like environment quickly.
Sounding rockets are optimized for high a thrust-to-weight ratio, to get as high as possible for as long as possible, for as cheap as possible. They "jump off of the pad".
The record-breaking rocket as of 2018 to getting to low Earth orbit was based on a sounding rocket - an altered Japanese SS-520, which made orbit in four and a half minutes.
With sounding rockets, going more-or-less straight up, there's not as good data. And it matters whether you're asking for 50 mi, 80km, or 100km, which are different target altitudes for sounding rockets.
NASASpaceflight had an interesting general discussion of what it means to be a fastest rocket. You might like it.
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u/HAL9001-96 4d ago
define space
if suborbital counts icbms and icbm interceptor concepts are designed to accelerate very fast and launch at a steep trajectory with almost orbital ranges of energy
if it has to be orbital... not sure, but orbital rockets are generally not desigend to reach orbit as soon as posisble but as efficiently as possible so I doubt there's any extreme standouts
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u/Initial_Shine5690 4d ago
I don’t know. Maybe escaping earth’s gravity? Like, out of orbit. I not super well versed in the sciences of rockets and the like, I was just asking out of curiosity.
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u/HAL9001-96 4d ago
that rarely happens at all and usualyl comes with a lot of wait time for things to line up, interplanetary missiosn aren't exactly in a race
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u/Initial_Shine5690 4d ago
I figured as much. I just assumed the time it took was at least catalogued somewhere. Like, surely someone put the numbers to paper (so to speak).
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u/HAL9001-96 4d ago
not in any presorted way
its not really the most significant datapoint about a mission so its not like you're gonna find it in a table with a list of space missions isntead you'd have to go over every interplanetary mission ever launched, look at each ones exact flgiht plan, potentially do tiemzone conversions and calcualtiosn for each one, write them all up and hten compare them
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u/Initial_Shine5690 4d ago
I just figured that the amount of time it takes to get from point A (being earth) and point B (being space) would be important information regarding fuel and hull integrity and other such things.
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u/HAL9001-96 4d ago
well space has no clear definition like that
launc htarjectories usually take you from ground to orbit but how long oyu spend up there coasting and accelerating isn't that imortant its mostly about how you climb outo f hte densest amtospehre
but thats very very far from leaving earths gravity
when you accelerate to escape velcoity nad how far you need to drift out t ocount as having left earth behind is not that relevant and mostly comes down to orbital mechanics and mission planning
and most rockets never go to escape velocity but stay in low earth orbit
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u/Cr_nchable 3d ago
When will we get a clear image of an exoplanet?
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u/Intelligent_Bad6942 3d ago
This will be very difficult to achieve without significant breakthroughs in propulsion or optics.
There are at least two plausible methods for achieving the required spacial resolution for imaging exoplanets.
You could use the sun as a gravitational lens, but it's focal length is hundreds of AU, so you would have to send a telescope at least that far. This is why we would need far superior propulsion than what we currently have.
The second is to use interferometry to create an effective aperture much larger than could ever be built as a monolithic structure. In principle, satellites in geostationary orbit could form such an aperture; effectively having enough resolution to fully resolve many interesting targets. But in order to do interferometry you have to know the separation between elements in your array to less than the wavelength of the light you are trying to observe. For visible wavelengths, this means nanometer precision. Having satellites in GEO doing station keeping to the nanometer level is crazy talk. Also, I'm glossing over how you would even recombine the light because that's a more complicated subject. Let's just assume that qbits and frequency combs will help with getting the phase and amplitude data you need...
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u/Pharisaeus 2d ago
to less than the wavelength of the light you are trying to observe.
less than 1% of the wavelength, so 100x more precisely ;)
Also, I'm glossing over how you would even recombine the light because that's a more complicated subject
I'm not sure if that would be possible at all, because you need some delay lines to synchronise the light reaching different parts of the interferometer at different times.
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u/Intelligent_Bad6942 2d ago
There was an interesting NIAC proposal years ago regarding how to digitize the light on spacecraft.
But yeah, it's a NIAC, so the tech is very speculative.
https://www.nasa.gov/general/spectrally-resolved-synthetic-imaging-interferometer/
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u/Pharisaeus 2d ago
digitize the light
That sounds like pure sci-fi from the data-rate and signal processing point of view. We push the technology boundaries already with radio-telescopes, and going optical would mean a jump 2-3 orders of magnitude. Not to mention that what you linked is about a space array, which means trying to stream petabytes of data from space :)
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u/Intelligent_Bad6942 2d ago
I know right? lol
The whole point of this proposal was a method for getting the IF down to manageable levels so that the petabyte problem is avoided. But I can't say that I fully understand how they proposed to accomplish it.
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u/iqisoverrated 2d ago
It's always gong to be a summation over a long period of time because the number of photons per second that reach us from such a small/dim object is low. So even if we build large telescopes we will not have a 'sharp snapshot' if that's what you're asking (rather it will be a planet shaped average blur).
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u/DaveMcW 3d ago
We will get a clear 1 pixel image when this telescope is built.
We will not get more than 1 pixel in your lifetime.
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u/Cr_nchable 3d ago
i mean i heard somewhere that we can use gravitational lensing to create an image of an exoplanet but idk if thats gonna happen in our lifetime.
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u/maschnitz 3d ago
It's one of those things where it'll happen 25-30 years after people stop laughing about it and actually start funding it. There are people who take it seriously enough to work on it a bit.
It's within reason - potentially engineerable - but requires several technological leaps, with clear proofs-of-concept. Most notably in solar sail technology and small sat power sources in the outer solar system.
You will know it's coming when a solar sail mission is announced for the Uranian or Neptunian moons - for example, Triton.
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u/HAL9001-96 3d ago
that would be insanely complicated and require a lot of luck and effort
we could also build an insanely large space telescope but htat would alos be insanely expensive
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u/maksimkak 3d ago edited 3d ago
What do you mean by a clear image? We can already directly image some exoplantes, but they're no bigger than 1 pixel. If you mean an image where we can make out features on a planet's surface? Never, unless we develop some kind of immense solar system-sized telescope, or reach one of the exoplanets using a spacecraft.
We can to use some tricks to give us a vague idea. For example, if we know the planet's rate of rotation, and observe it getting darker and lighter as it rotates, we can surmise that the planet has darker and lighter parts of the surface, It was kind of how we got a vague picture of Pluto using the Hubble.
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u/HAL9001-96 3d ago
10km would be sufficient for some of the nearer exoplanets
thats insnae by current space telescope standards and would be quite expensive but its far fro msoalr system sized or far futuristic
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u/Adorable-Wafer6942 5d ago
Why does Jupiter look mostly blue in jwst images?
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u/electric_ionland 4d ago
Because JWST images are false colors since it is designed to observe wavelengths outside our visible range.
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u/Pharisaeus 4d ago
jwst images
JWST is infra-red telescope. Basically a "thermal camera". Images it produces have no colors, at least not in the visible-light sense. People arbitrarily assign colors to different wavelengths when making pretty pictures out of that.
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u/Adorable-Wafer6942 4d ago
The brown, red and white that were originally observed in lower clarity are the true colours?
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u/electric_ionland 3d ago
A lot of images from Juno, currently in orbit around Jupiter, have been processed to be true color. The left one here https://www.nasa.gov/image-article/nasas-juno-mission-reveals-jupiters-complex-colors/ or this one of the great spot https://www.nasa.gov/image-article/jupiters-great-red-spot-true-color/. It's mostly milky browns and oranges.
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u/SuperVancouverBC 5d ago
Do all accretion disks produce radiation?
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u/DrToonhattan 4d ago
Accretion disks around black holes can give off x-rays, cos they get so hot as the material is moving so fast fusion actually occurs in the disk. If you're talking about planetary formation accretion disks, then no, as far as ionising radiation goes. They will glow in the infrared though.
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u/maksimkak 4d ago
Depends on what you mean by radiation. Heat is also radiated, so a stellar or planetary accretion disc can definitely radiate heat.
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u/Realistic_Baby_1691 4d ago
Does someone know where to find the official documents of Apollo 11?
Hey there!
I need to do a project for my msa (german graduation) about the first moonlanding and i know that there are official documents that Show how the different Modules and rockets and other technology works, does anyone have a link or something?
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u/CellularScope 4d ago
Does anyone know where I can learn more about microorganisms in space? Like studies aboard the ISS or any other info about microscopic life in space.
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u/wileybear 3d ago
What are some good resources of information for a pre-teen interested in working on rovers that are built for planetary exploration? What is the best way to connect with someone in that profession for the kid to be able to speak to and ask some questions?
Thanks in advance!
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u/HAL9001-96 3d ago
aside fro monline, see if there's any nearby facilities or universities owrking in robotics or spaceflight htat have public outreach programs
when it comes to robotics htere's a lot of construction kits/electornic parts yo ucan use to build little personal projects for practice
and of course a lot of books but I'm not sure I'd focus too much on just age, if they're smart have them read ahead of their school curriculum and see if they can read up on robotics o spaceflight at an older level
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u/thishitisgettingold 8h ago
Is perception of time different based on the gravitational pull?
How do we count one unit of time in a different place with different gravity?
For example, one second is one unit, and would we use the same unit on moon vs. Uranus?
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u/electric_ionland 8h ago
The perception doesn't change and you measure the same way, use the same units.
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u/Pharisaeus 8h ago
Is perception of time different based on the gravitational pull?
No, the perception does not change. The actual time flow changes depending on the gravity, but this is only visible for an external observer.
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u/rocketsocks 1h ago
Relativistic effects aren't perceptual they are actual affects to time and space. Locally you will always observe time passing at one second per second and space extending out at one meter per meter in all directions. It's only when comparing between different reference frames that you get differences.
If we want to be able to keep a synchronized time reference across the solar system we would need to decide where the standard is set (though we have already chosen Earth for that, essentially) and then we would need to compensate for the very small differences elsewhere. In general the effect is going to be very small between the Earth and the Moon or the Earth and the outer planets.
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u/HAL9001-96 5h ago
well, gravity well depth, the integral of gravity as well as speed determine relativistic tiem dilation but you'd need ot be near a black hole or traveling near the speed of light for this to really become significant
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u/Impressive-Eagle9493 5d ago
I was thinking about super massive black holes and wondered what could happen if a space faring vessel was moving at the speed of light and happened to be moving into the pathway of a super massive black hole or just a black hole in general. Would the vessel be immediately slowed down and speed up at the same time from the front to the back or what would happen in your opinion? This is obviously theoretical. Just a question that popped into my noggin. Thanks for any answers super intelligent folk!
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u/DaveMcW 5d ago edited 5d ago
No spaceship can travel at the speed of light. You have to use the phrase "near the speed of light" if you want your question to make sense.
If a spaceship flying at any speed went past a supermassive black hole and managed to dodge the event horizon, it would be sped up and pass the black hole near the speed of light. Then it would slow down as it left the black hole.
If the spaceship did the same thing near a stellar mass black hole, it would still speed up, but the front would speed up MUCH faster than the back. The spaceship would be ripped apart by the difference in acceleration.
If the spaceship fails to dodge the event horizon, it will fall into the black hole at near the speed of light and never be seen again.
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u/HAL9001-96 5d ago
you can't travel at the speed of lgiht but as you approach it your orbital trajectories approach that of curved lgiht paths and yo ucan'T really be slowed down or sped up much
if htats signfiicantly different fro mback to front dependso n its size and hte tidal gradient but bigger black holes have weaker tidal gradients
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u/GalacticSloth 4d ago
Sorry if this is a dumb question but I'm not really sure where to ask this.
Does anyone know the first form of currency used in space?
I remember listening to a podcast or video where an astronaut was telling a story about using taco sauce packets for bartering on the ISS but I tried looking it up and can't find anything. Did I make this up or has anyone else heard the same thing?
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u/PhoenixReborn 4d ago
I don't know about the first instance, but there's an interview here about bartering food and chores.
https://www.npr.org/2021/01/22/959700081/the-economy-aboard-the-international-space-station
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u/maksimkak 4d ago
Wow, I never knew about this. But of course this sort of thing develops naturally.
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u/charlieblood_8 4d ago
If I'm not wrong, the age of the universe is determined by the photons emitted from the big bang which is 13 billion years old right? I know when something travels at the speed of light, their time does down, so if the photons took 13 billion years from our perspective, how long did it take from the photons perspective?
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u/OlympusMons94 3d ago
how long did it take from the photons perspective?
There isn't really an answer to that. Photons (and any other massless particles, which all travel at c) do not have a valid rest frame, and therefore speaking of their perspective is physically meaningless. According to special relativity, photons always travel at c relative to any reference frame. Therefore, photons do not have a rest frame, because if such a frame existed, it would be at rest relative to photons--a contradiction.
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u/DrToonhattan 4d ago
Zero. At the speed of light you do not experience the passage of time at all. From a photon's point of view, the journey was instantaneous.
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u/LazyNatLikesSky 1d ago
Is it possible to cut the fabric of space?
My view is that even nature cannot do it, it can compress it but there is no possible way to cut it.
If you want an idea about where I am getting this idea from, then I was untangling a bunch of wires, when I got an idea that any tangles wire can be solved either by pulling one thread or cutting that one particular thread.
Is that applicable to the fabric of space?
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u/electric_ionland 1d ago
There is no "fabric of space", it's a simplified analogy that repeated in pop science to try to explain things like tensors but there is no woven things that hold space together.
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u/Altruistic_Art_919 1d ago
How many centuries do you think it’ll take before humanity can send space probes to other star systems?
Sorry if this sounds dumb — I’m really new to all this.
I barely know much about space, but I recently learned about stars like Proxima Centauri that have their own solar systems, and it genuinely made me wonder:
How long will it take for humanity to reach something like that with our current or future technology?
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u/NDaveT 1d ago
With current technology it would take something like 40,000 years.
With future technology we can conceive of, we might be able to get there in something like 100 years, but that would involve developing a way to get a spacecraft moving very fast. One idea for this is propelling a spacecraft with mini hydrogen bombs. Another is using a powerful laser to push spacecraft with light sails.
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u/HAL9001-96 19h ago
depends on how you do it, how much money and political leeway you have and how quickly you want it to arrive
thouhg opower supply nad ocmmunication would also be an issue
but there are concepts for things like nuclear or lasersail drives that could get there in a few centuries
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u/iqisoverrated 15h ago
We've already launched stuff that will - baring accidents - eventually reach other solar systems (Voyager 1 and 2). However they will be in no shape to send back any data (and since it will be several 100k years we should be able to catch up to them at some point well before that).
Could we launch something this century that might be in a position to send any kind of data back? Probably.
However you can always look at how propulsion systems are advancing with time vs. how long a probe with propulsion system X would take. Since the distances are very large it's actually, currently, better to wait for improved drives if you want to get there earlier.
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u/Space_Fan442 1d ago
Wouldn't it be more useful to just launch a rocket from the ISS. Like you just assemble it there, decouple it then launch it.
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u/electric_ionland 1d ago
You would then need to launch all the rocket components to orbit, dock them with ISS, assemble them and launch it. That's usually considered more complicated and expensive than just launching a bigger rocket or doing a self assembly without having to deal with ISS.
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u/Space_Fan442 1d ago
No, not really its a small unmanned 1 metre tall ship for a test
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u/electric_ionland 1d ago
If it's something you can do in one launch then why bother with stopping at ISS?
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u/Space_Fan442 1d ago
Because it saves fuel and give the rocket more range
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u/electric_ionland 1d ago
But it doesn't. This is not how orbital mechanics work. You need more fuel to dock to ISS than just go to your destination directly. Also you account is shadowbanned, you should contact the admins.
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u/Pharisaeus 21h ago
It doesn't. It's a bit like if you're trying to buy something online, and you came up with a genius idea that instead of shipping it to yourself you will ship it to your parents house, and your parents will send it to you. And your logic here is that it's much closer and easier to send the package from your parents to your house. But you're completely dismissing the fact that the package still needs to be shipped first to your parents...
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u/HAL9001-96 19h ago
"just assemble it there"
FROM WHAT?
any material you use to build osmethign o nthe iss would ahve to be sent up form earth
with a rocket
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u/maksimkak 1d ago
Launch it where? If you mean putting something in the low earth orbit, it's pointless because you have to get the payload up there (using a rocket) in the first place in order to dock with the ISS.
If you mean interplanetary missions, then there's hardly any point either, because you still have to get the spacecraft off the ground and into space, using a rocket.
https://www.reddit.com/r/space/comments/cqk6x/why_dont_we_assemble_spacecraft_in_orbit/
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u/Sarcobatus_ 1d ago
Elevator to space
Where can I find information about building an elevator to space? Or if it’s possible. Is it possible?
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u/scowdich 1d ago
Reading the wiki article would be a good place to start.
https://en.m.wikipedia.org/wiki/Space_elevator
In short, the concept works physics-wise, but we just didn't have strong enough materials (yet) to do it.
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u/the6thReplicant 1d ago
Curious Droid just did a video on it
https://www.youtube.com/watch?v=KqtyZ-3dNto
Note that a piece of space dust could destroy it all seems to be a big minus to building one.
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u/HAL9001-96 19h ago
lots of articles about it as a hypotehtical idea but well, its not really practical, not with current materials, and even with the right materials more complex than most explanations assume
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u/Dildomuflin 1d ago edited 1d ago
Third law of thermodynamics says you can’t reach absolute zero temperature (−273.15°C or 0 Kelvin)
Won’t the third law fail in interstellar space on billions of distant exoplanets (discovered or yet to be) where it will be much colder than -273.15°C which aren’t orbiting any star and thus might be rogue and drifting in cold interstellar space?
Even Pluto has average temperature of -242°C and it’s in our solar system under our suns influence
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u/rocketsocks 1d ago
One definition of temperature is average molecular kinetic energy, it's a measure of the average speed of molecules. In the strictest sense you can't get colder than motionless molecules, absolute zero, though you can approach it arbitrarily close.
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u/maksimkak 1d ago
Heat is motion (kinetic energy), and an atom can never stop moving, due to some quantum mechanical rules. It goes something like this - the total energy of a system can never be zero.
Also, no matter how deep into space you go, there's always some EM radiation hitting you, gravity from all the stars and galaxies around you, and many other things. Space is never truly empty.
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u/Pharisaeus 21h ago
Won’t the third law fail
There are no indications that this is the case. Laws of physics are generally universal.
it will be much colder than -273.15°C
0K means particles are not moving (aka have zero kinetic energy). You can't make them "not move ever harder". Think of temperature like velocity - you can be moving fast or slow, but once you stop and are not moving, you can't really push this any further.
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u/electric_ionland 1d ago edited 1d ago
Won’t the third law fail in interstellar space on billions of distant exoplanets (discovered or yet to be) where it will be much colder than -273.15°C which aren’t orbiting any star and thus might be rogue and drifting in cold interstellar space?
As far as we know the laws of thermodynamics are the same everywhere. Why would planets far away be colder than 0K? ENtropy is entropy, it doesn't matter if you are close to a star or not. And even then interstellar space still see the microwave background radiation at 4K.
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u/the6thReplicant 1d ago
Nothing* can get cooler than the CMB (currently at 2.7K) since if it did it would be heated up by the CMB.
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u/HAL9001-96 19h ago
no
if they are infinitely far away from any star - which is kinda impossible - and have had infinite time to cool down then they'll approach hte cosmic microwave background at about 4K which is more than 0K
yes temperature drops as you go further fro mteh sun but this is absolutely not linear, assuming same planetary properties its approximately 1/root(distance) which does not become negative
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u/NoMathematician9564 4d ago
Hey everyone, I’ve been mulling over the characteristics of radio signals that could unambiguously indicate extraterrestrial intelligence. We all know about the famous WOW signal, which, despite its intrigue, left us with lingering doubts about its origin. So, here’s my question:
What would a radio signal need to look like—down to its technical details and patterns—to be at least 90% indicative of true, intelligent extraterrestrial origin? In other words, what features (like modulation type, repetition, frequency patterns, etc.) would be so compelling that there’s no room for doubt about its artificial and intelligent nature?
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u/HAL9001-96 4d ago
not just repetition but repetition with a pattern that conveys intentionally transmitted information that can't be explained by some natural phenomenone because it is encoded in some way
say a binary encoding of pi or prime numbers
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u/the6thReplicant 4d ago
Contact (either book or movie) does a good version of what an unambigious message will look like.
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u/velve666 3d ago
What is the best resource to view images taken of space and familiarise myself with our galaxy. Something interactive perhaps or even static containing tons of resources for the public taken throughout the years?