Building telescopes on the Moon could transform astronomy

https://theconversation.com/building-telescopes-on-the-moon-could-transform-astronomy-and-its-becoming-an-achievable-goal-203308

by CharlesW • 3 years ago

242 149 3 years ago

theconversation.com

freeqaz• 3 years ago

Man, this really excites me! I hadn't even thought about this before, but it seems super obvious now. Especially the bit in the article about putting a telescope at one of the poles inside of a crater (to shield from sunlight).

I'm surprised this proposal hasn't been tried sooner. Is this because the cost per pound to send something into space has gotten cheaper? Why now?

enlyth• 3 years ago

Also, Earth's sky will eventually get polluted by things like SpaceX satellites, so this would solve that issue as well.

BurningFrog• 3 years ago

Putting telescopes in higher orbits should handle most of that.

Rebelgecko2• 3 years ago

Once Starlink builds up the capacity around the moon to handle all the new telescopes' data, won't they have the same problem?

oh_sigh• 3 years ago

If there were a million satellites(which there won't be), and they averaged 100 square meters each (which they don't), and they were all very close to earth in LEO(like starlink, which they aren't), they would take up 0.0000166% of the night sky.

I think we will be okay.

schiffern• 3 years ago

polluted by things like SpaceX satellites

I know the media likes to hyper-focus on SpaceX, but it should be noted that Starlink is one of the best large constellations in this regard. SpaceX goes far above and beyond the (inadequate IMO) legal requirements for radio/IR/visible emanations, at substantial engineering expense to themselves.

https://youtu.be/MNc5yCYth5E?t=1717

https://cps.iau.org/news/nsf-and-spacex-sign-agreement-to-mi...

If you really want to get mad about badly-designed satellites impacting astronomy, look up AST SpaceMobile.

Maursault2• 3 years ago

Discussion began here 9 hours ago: https://news.ycombinator.com/item?id=35627234

Why is HN taking after reddit so much lately with duplicates?

dabluecaboose• 3 years ago

redditors fleeing the eternal september on their site and unintentionally causing one on HN

flangola72• 3 years ago

What is the eternal September of Reddit?

double2helix• 3 years ago

The catch-22 is the influx of lunar traffic will create some noise interference on the "dark side" of the moon. Still less than that on earth though.

jrussino• 3 years ago

This was my first thought when reading the article.

The lunar far side is permanently shielded from the radio signals generated by humans on Earth. During the lunar night, it is also protected from the Sun. These characteristics make it probably the most “radio-quiet” location in the whole solar system as no other planet or moon has a side that permanently faces away from the Earth. It is therefore ideally suited for radio astronomy.

Maybe we need to treat this as a "pristine natural resource" and put some treaties in place now where we agree to limit how much we "pollute" this area with RF signals, before it's too late?

joering22• 3 years ago

define "too late" ?

httpz2• 3 years ago

China already has a rover on the far side of the moon so my hopes aren't high.

quickthrower22• 3 years ago

Maybe have RF curfews, 6pm to 6am GMT every day.

csours• 3 years ago

No mention of dust. The lunar astronauts complained about the stuff. There's some weird stuff due to electrical charges not being able to dissipate.

I do hope we try it though, speaking from my inner 12 year old.

psychphysic• 3 years ago

The charge that causes the issue can also be used to fix it

https://science.nasa.gov/science-news/science-at-nasa/2006/1...

It would be pretty sweet to have a decent scope on the far side of the moon.

Teever• 3 years ago

I can't find it right now but I read a paper that said that even moderate exploration activity on the moon, let alone colonization and industrialization will kick up a moderate amount of dust that will linger for thousands of years.

I don't know if this will affect moon based telescopes in a way that can't be mitigated tough.

pengaru3• 3 years ago

That's a really clever solution. I wonder why they haven't deployed this on the Mars rover solar panels?

milleramp• 3 years ago

I thought of this as well but for radio astronomy it may not be a big problem. The wavelengths are so large. Not sure if dust would degrade antenna performance enough to be a issue.

hiccuphippo• 3 years ago

What are the chances of meteorites being a threat? Without an atmosphere it is easier for them to reach the ground and cause damage.

joering22• 3 years ago

As my understanding goes, Moon is very big and meteors are very small and aim/crash rarely. You can look at its surface and assume there is activity all the time but because of lack of atmosphere anything that touches the surface leaves footprints for thousands of years. Armstrong footprint is still there.

cdot2• 3 years ago

More like millions of years

lamontcg• 3 years ago

more or less the same problem JWST or anything else in space faces.

rkwasny• 3 years ago

What? we have a telescope in L2 point(the second Lagrangian point)! it is soo much better there compared to the moon

autokad• 3 years ago

if we could manufacture the telescopes on the moon, we could build massive ones (and size matters). And, why not have both?

post-it• 3 years ago

Couldn't we manufacture more massive ones in orbit around the moon, since they won't collapse under their own weight? We'd need extra fuel to get resources or parts off the surface of the moon, but that's nothing in comparison to the fuel needed to get off the Earth.

Edit: I forgot the moon has a much lower gravity than Earth. It might still be worthwhile to build in orbit, but we can build a lot bigger on the moon than on Earth.

shagie7• 3 years ago

A radio telescope on the scale of Arecibo - where you are after extremely large surface area for detection of faint signals - is limited by the size of the dish.

Arecibo was 73,000 square meters while JWST is "only" 25 square meters.

For this, building it in a crater on the moon and allowing the moon itself to help support it is advantageous.

... and has some interesting scaling up possible.

https://www.researchgate.net/publication/258694444_Implement...

kristianp• 3 years ago

They mention NASAs Artemis program, but the real enabler of larger payloads to the moon may be SpaceX Starship, not SLS, which is too expensive and can't be launched often enough to be used for any additional missions to those already scheduled.

SECProto• 3 years ago

They mention NASAs Artemis program, but the real enabler of larger payloads to the moon may be SpaceX Starship, not SLS

Note that the two aren't mutually exclusive: Artemis 3 uses [1] Starship as a major component, and it's likely that Starship will take over other parts of the works for the reason you note.

[1] https://en.wikipedia.org/wiki/Artemis_3

m3kw9• 3 years ago

They need some spaced based weapons when exploring the far side of the moon, you never know

samstave3• 3 years ago

totally stupid question:

Could one theoretically point the hubble at the james webb mirrors and see anything?

CalChris• 3 years ago

No.

The JWST is about a million miles away from earth. It is only 6.5 meters wide.

  tan = 6.5 meters / 1M miles = 4.03891275 × 10-9

  2.31×10^-7 degrees

The Hubble can resolve 1/10th of an arc second or

  2.78×10^-5 degrees

So it's roughly 100 times too small for the Hubble to see.

samstave3• 3 years ago

thank you

kristopolous2• 3 years ago

There's more. The triangulations would provide some really great confirmation and precision on a number of things.

The unanswered question is if this is blocked out from earth communication, what are you doing for earth communication? Moon satellites? Optical relays? Would it go to the Mars satellites? These things get booked so far ahead of time, you can probably pretty easily schedule the dark times when it couldn't talk to Mars especially if you send it up with modern storage tech.

I guess there's also Venus satellites coming around soon as well.

gumby• 3 years ago

Why not put relay satellites that orbit the moon?

Actually I think this is already being planned anyway, unrelated to a telescope.

pixl97• 3 years ago

The moon is insanely hard to orbit because it's gravity is very lumpy

https://www.nasa.gov/feature/does-anything-orbit-the-moon-we...

OkayPhysicist• 3 years ago

It would probably be cheaper to put several relay satellites in extra-lunar orbits around Earth. Earth's gravity has a tendency to complicate lunar orbits.

jwuphysics• 3 years ago

Satellites are also one of the biggest sources of radio frequency interference. (I did my PhD in radio astronomy and currently work on multiwavelength astronomy.)

zokier• 3 years ago

There is no shortage of lunar communication satellite projects. ESA has Moonlight/Pathfinder, NASA has LCRNS/LunaNet, CNCA has its own projects (e.g. Queqiao), and there are even private efforts.

dflock• 3 years ago

I'd just run a bundle of optical fibre cables over the horizon to the nearside and transmit to earth from there?

httpz2• 3 years ago

So you're telling me instead of the fragile and complicated shield on the James Webb Telescope, we could've used the entire moon as a shield?

asdfman1233• 3 years ago

Are you a software developer? If so, I’m sure you understand the perils of a solution that sounds easy.

micromacrofoot• 3 years ago

moons a much more dense target

sega_sai• 3 years ago

You know that the other side of the moon gets exposed to the Sun, right?

nealabq2• 3 years ago

And the moon's too hot anyway. Even at the end of its long night. Even at -130C it'd still be too hot for JWST.

simonh• 3 years ago

The article suggests using polar craters that remain in shadow. That would limit your field of view quite a bit though.

jjtheblunt• 3 years ago

Really ignorant question: some comments mention huge telescopes: can a moon be used via gravitational lens-ing to effect a huge telescope?

sandworm1013• 3 years ago

No. The focal point would be so far away, as in way bigger that the moon's orbit, that the entire arrangement would be wildly impractical. Imagine hanging out around pluto's orbit while trying to aim at earths moon as it spins around the earth. Using the earth would be easier. Using jupiter would be easier.

It is possible to build a refracting telescope in space that uses earths atmosphere as a lens. This is far more practical (ie smaller) than any gravity telescope.

tadfisher2• 3 years ago

The sun's focal point is 542 AU, about 11 times Pluto's orbit. It's safe to say we won't be using Jupiter or Earth as lenses anytime soon.

tadfisher2• 3 years ago

The lens effect from something less massive than a star is too weak. The Sun has a focal point 542 AU away from its center; our moon would have a focal point some orders of magnitude beyond that, and the angular resolution wouldn't be nearly as good.

In short, it's far easier and more effective to use the Sun for this effect. Radio interferometry would be a better use for Moon-based observatories, if we felt like building several of them.

supernova87a2• 3 years ago

I hate to say it (as someone formerly from this field), but --

Astronomers can justify any amount of spending you ask them to, based on whatever incremental learning a telescope of a new type can be built for, based on:

-- size of telescope

-- new sensors

-- background noise reduction, sensitivity

-- frequency domain, spectroscopic resolution

-- it goes on and on

Who provides the external check of whether the latest improvement is worth spending the money? Because astronomers will always say it's worth it on some dimension. How do we decide whether that dimension is worth the money?

Is pushing the discovery of some metal content in an early galaxy by one more unit of redshift worth $10B? Study of dust obscuration of some nebula really pushing the boundaries of our understanding like it was 50 years ago? (or similar esoteric questions)

What $ / unit scientific discovery is worth it?

Edit to add: and yes there are things like the decadal survey and the “industry” has to justify itself to Congress (in the US at least). And yes, I generally do think the finding of this is (at these levels) probably going to bring some net positive multiplier benefit even if hard to quantify. And is more value per money than sending it to war to use an extreme comparison. But I wish there were a more defensible bar for knowing, other than public opinion or “at least we’re not as much a waste as <xyz>”.

Just lucky for astronomy that at least they produce pet pictures for the public to support. But sad for other important fields that don’t have this luxury.

brutusborn3• 3 years ago

I remember listening to a talk where the presenter suggested the history of radio telescopes development was driven by the need for intelligence gathering. The telescopes could be used for spying but were justified on a scientific basis.

I imagine a lot of space development is similar. The real reason for the huge investment is for defence applications, but it is more acceptable to justify it by the scientific ‘value’ of the projects.

If you asked someone if they wanted $1billion to go to health research or space research the answer would be obvious.

htag• 3 years ago

If you asked someone if they wanted $1billion to go to health research or space research the answer would be obvious.

Honestly this depends. If we have 1000 billion going into health research, but 1 billion doing into space research, I think there's an open question on how much good an extra 0.1% of health research will do compared to doubling space research.

In absolute terms instead of relative, I would prefer a billion on most space based research than a billion going to study male pattern baldness.

beerandt• 3 years ago

Pretty much all serious science spending is actually military spending. People don't always like to admit that, though, even when it's obvious.

More so when it's not obvious.

XorNot2• 3 years ago

The US actually built at least 9 Hubble Space Telescopes, they're just not called that: they're called Keyhole surveillance satellites.

The size and shape of the Hubble is directly influenced by those satellites, and in particular the surprisingly cheap main mirror optics provided you built a mirror of exactly a particular size that it would turn out there was a very experienced and equipped facility in the US for building.

supernova87a2• 3 years ago

Here's that talk:

"Secret History of Silicon Valley" https://www.youtube.com/watch?v=ZTC_RxWN_xo

ultra_nick• 3 years ago

Investors have a tool for that.

The scientific betting principal could be used to optimally size bets on which research will benefit humanity the most.

https://en.m.wikipedia.org/wiki/Kelly_criterion

dmix3• 3 years ago

I've always wondered how that works. I'm all for full bore public spending on space but sometimes when you read the list of the research goals for NASA/EU spending hundreds of millions on getting to Jupiter (for ex) I often wonder "that's it"? But then I remind myself I don't know anything about this stuff compared to the people doing it as their job and assume the scientists/admins have some set of priorities which are essential in the process for some bigger important stuff.

My biggest question is why they aren't putting tons of pressure on getting a telescope that can do gravitational lensing to see as far into space as possible ASAP. But again I'm probably just speaking out of turn not being familiar with the wider industry/culture/economics.

shagie7• 3 years ago

My biggest question is why they aren't putting tons of pressure on getting a telescope that can do gravitational lensing to see as far into space as possible ASAP. But again I'm probably just speaking out of turn not being familiar with the wider industry/culture/economics.

You are likely interested in the FOCAL project. https://en.wikipedia.org/wiki/FOCAL_(spacecraft)

FOCAL (an acronym for Fast Outgoing Cyclopean Astronomical Lens) is a proposed space telescope that would use the Sun as a gravity lens. The gravitational lens effect was first derived by Albert Einstein, and the concept of a mission to the solar gravitational lens was first suggested by professor Von Eshleman, and analyzed further by Italian astronomer Claudio Maccone and others.
In order to use the Sun as a gravity lens, it would be necessary to send the telescope to a minimum distance of 550 astronomical units away from the Sun, enabling very high signal amplifications: for example, at the 203 GHz wavelength, amplification of 1.3 x 10^15. Maccone suggests that this should be enough to obtain detailed images of the surfaces of extrasolar planets.

---

That 550 AU... for comparison, Voyager 1 is currently at about 159 AU and moving at 3.6 AU/year.

New Horizons is "only" 55.6 AU and going at 2.9 AU/year.

But its an interesting project.

Mistletoe• 3 years ago

I say revisit it when we don’t have billions in poverty, global climate change is tamed, cancer is significantly reduced, etc. I can’t justify a living breathing human dying on our planet right here as we probe the minutiae of the universe looking for things that are largely meaningless at this point. It’s not that I don’t find research like that fascinating, it’s just that I find life that is here even more precious and fascinating.

wpietri• 3 years ago

Unfortunately, I don't think there's any point in history where this heuristic would have allowed for significant basic research. But looking at the modern world, there's no way we could support today's population without some of that basic research.

Regardless, poverty isn't mainly a problem of wealth scarcity, but instead of wealth distribution. So even if you stopped spending on any research that doesn't have a short-term justification, I don't think that money would end up alleviating poverty, but instead going to fund somebody's slightly bigger superyacht.

prox2• 3 years ago

I have to disagree strongly. My take on this that navel staring is a source of the problems you mention. We are so hopelessly fascinated by internal conflict that having a more telescopic view and/or grand horizon view of what Earth’s place is, and our what should be a brotherhood of mankind is that we don’t have enough of that.

Instead I get flipping news about stupid Kardashians or some navel gazing shit like wars, stupid ideologies, etc. etc. all day, every day.

throwawayastro• 3 years ago

As someone also formerly in the field, I agree but also that’s sort of what funding agencies are for? You have finite funding, where is the best place to put that money? Yes you can find any number of astronomers interested in spending money better spent elsewhere but my impression of the field as a whole when I left was that there were far more genuinely important projects not funded than bad projects funded.

geuis• 3 years ago

(I'm not dismissing, your position, just adding context.)

A very similar argument can be made for particle physics and their colliders. Yes, telescopes produce pretty pictures, but fundamental particle physics occasionally produces practical results.

Well, they used to (the colliders I mean). Modern particle physics seems to be more in the confirmation stage of current theory rather than a discovery phase like it used to be maybe 40 years ago.

Meanwhile astronomy keeps opening up new questions about the universe that require even better equipment to attempt to answer.

Building better colliders and better telescopes are interesting end goals, but also consider what goes along with them.

Building them means funding multiple generations of new theorists and engineers. A lot of those people do fundamental research and then branch out to both found new commercial companies based on those discoveries and to work for those companies.

I think it's better to look at "big science" in a much broader perspective. The new collider or telescope might "cost" $10 billion, but that isn't the cost of building the machine and its materials.

Most of that money goes into paying people across a very diverse field of professions to do the research and engineering required to make that big pretty picture machine work. That's the stuff that drives technical innovations at the edge of what we apes currently understand.

When we fall back to asking why build pyramids, cathedrals, highways, rockets, or anything else that requires a vast number of people to work towards the same goal, don't forget about what everyone gets from the journey on the way.

hinkley2• 3 years ago

Isn't Gorilla Glass effectively particle physics?

There's a ton of surface treatment in materials science that amounts to firing a beam of atoms at a surface and/or bathing it in a plasma in order to get a unique chemical structure.

bruce511• 3 years ago

Also, I guess it's worth pointing out, that the sums of money involved are in a relative sense very small.

The James Webb telescope cost 10 billion, but that was spent over 17 years, and it should work for 20 years or so.

Compared to the budget as a whole, it is insignificant.

And the pretty pictures do serve a wider purpose. They will be part of the space inspiration for the next generation. Out there are kids dreaming of space, and the opportunities there etc.

Who knows, maybe the first asteroid miner is already with us, inspired by some James Webb picture on his bedroom wall.

LegitShady3• 3 years ago

A very similar argument can be made for particle physics and their colliders. Yes, telescopes produce pretty pictures, but fundamental particle physics occasionally produces practical results.
Well, they used to (the colliders I mean). Modern particle physics seems to be more in the confirmation stage of current theory rather than a discovery phase like it used to be maybe 40 years ago.

There are some good arguments as to why a muon collider might be a really good thing to build, and why it would be smaller than the LHC. CERN already has a program to look into it.

If you have an hour this is a good talk by Nima Arkani-Hamed about muon colliders from last month. https://www.youtube.com/watch?v=wKPwzezceGo&t=3379s

But to address your point about being in the confirmation phase, you can go to this particular time stamp, where he talks about why a muon collider is a good way to probe the higgs boson itself, which is new science.

https://youtu.be/wKPwzezceGo?t=618

wolverine876• 3 years ago

How does that differ from any request for funding in any field, public or private. It applies to everyone seeking funding from the public (via Congress), to people seeking funding from grant-making organizations, to people seeking funding from banks, from VCs, etc.

Everyone has a story on how they will provide value, and the funders must decide who offers the best ROI.

DiogenesKynikos2• 3 years ago

In the American astronomy community, there is a process every 10 years to determine what should be prioritized over the next decade. It's called the Decadal Survey.[0]

The Decadal Survey does not determine the overall level of funding for astronomy. It just says, "If you gave us X amount of money, here's how we would divide it up, based on what we think are the most important questions in our field." There's a competitive process within the community to propose projects and argue for different scientific research areas, which eventually gets distilled down into a set of funding recommendations.

The Decadal Survey is really just a recommendation to the funding agencies, which can ignore it if they wish. However, since it does represent the consensus of American astronomers, it's taken very seriously.

As for the overall level of astronomy funding, astronomers have very little control over that. That's decided at a political level, by Congress, and I doubt there's any rigorous cost-benefit analysis to society going on there.

0. https://www.nationalacademies.org/our-work/decadal-survey-on...

brokeAstronomer3• 3 years ago

As someone in the field (I made an account just to comment on this), I agree that scientists will always be motivated to push the boundaries on questions that are relatively esoteric. People are right to be skeptical... However, even if they aren't immediate, there are enormous tangible benefits to society from conducting scientific research:

1. Basic research directly underpins the vast majority of the technology we have available. Or at the minimum provides the framework with which we understand how technology operates, making it easier to improve. I think the utility of this is greatly underappreciated.

2. It's impossible to know in advance how useful some basic piece of research will prove to be in the future. We can only guess at the $ value, and many of the most useful results are surprises from blue-sky research not applied goal-orientated work.

3. Academia produces an army of highly-trained disgruntled postdocs and PhD students (just look at the ratio of student to professor positions) who have beneficial transferable skills for industry. It's not that you can't learn to do research outside of the academic environment, but getting a PhD is good training for it.

Finally, just guessing here, but did you work on galaxies or the ISM? We're on the cusp (a couple of decades) from imaging potentially habitable Earth analogs with next-generation space missions. This is a huge step toward answering the 'are we alone' question. Personally, I'd happily spend a few billion on that though I know not everyone would agree...

stef25• 3 years ago

We're on the cusp (a couple of decades) from imaging potentially habitable Earth analogs with next-generation space missions

Would love to hear more!

xhkkffbf• 3 years ago

Why is getting a PhD good training for being a disgruntled and unemployed post-doc? Why should society spend sooo much money training someone and filling their heads with knowledge only to just kick that person out of science? It is a horrible mystery why people like you feel this is a good way to run society.

vogon_laureate• 3 years ago

Hubble’s images has inspired millions. We should be happy to invest in things that spark wonder and awe. It’s good for humanity.

poulpy123• 3 years ago

Who provides the external check of whether the latest improvement is worth spending the money? Because astronomers will always say it's worth it on some dimension. How do we decide whether that dimension is worth the money?

I'm surprised you don't know that as someone from the field.

On the general level, it is the elected politicians that decide of the budget of the state, and which part goes to science and to which science branch. On the specific level, it's the science organizations (usually staffed by scientists) that decide who get what based on the quality of scientific proposals.

Scientists don't get money just because. They have to write lengthy proposals justifying their requests. These proposals are examined by other scientists and compared to others, and the most promising are awarded money. It can take decades to go from an idea to having a project funded.

Also there is no "unit scientific discovery" so no $/unit scientific discovery can be evaluated

xchip• 3 years ago

Physicist here, I agree with you 100%

travisporter• 3 years ago

So scientists want better instruments to work with. Why is that a crime? Even CERN may be a huge expense. Idk even now I think Michelson and Morley’s ether experiment was worth it.

8bitsrule• 3 years ago

I've noticed that 'water' is often discovered in places where people want to spend money to scrutinize/get to. (For a variety of reasons.)

E.g. sometimes vast internal 'oceans' are somehow implied by water vapor escaping from the surface of a moon. For the sake of visiting astronauts, I hope some of this 'water' turns out to be real.

(Wherever the water in the Earth's oceans really came from is at least, finally, being questioned.)

bee_rider• 3 years ago

This comment confuses me.

Why is water in scare-quotes? Is the implication that it is something other than water?

Is there a supposed meaning behind this tendency to look for water in places? I assume any sufficiently large celestial body gets a bit of eyeball time, and the ones that have water are bumped into the “interesting” bin because if we hypothetically ever hope to go there, that’s one necessary thing for survival off the list.

What is the last parenthetical about? The water on Earth was at some point in space, after all, there’s no alternative…

causality0• 3 years ago

After JWST ran thousands of percent over budget and decades behind schedule I'm tempted to suspect any new telescope project of being a grift. If they get Congressional approval for a fifteen billion dollar lunar telescope it's going to end up costing fifty billion and somehow that won't result in anybody going to prison.

dylan6042• 3 years ago

JWST was being built with the knowledge that there would be no way we could ever get to it to make repairs. A telescope on the moon would be something we could send the Maytag repair guy to make a house call. The risk is much smaller

whatshisface2• 3 years ago

By "maytag repair guy" do you mean a billion dollar manned lunar program? ;)

midoridensha2• 3 years ago

Exactly: once we have a Moon base, it won't be hard to send technicians to the dark side to repair the radio telescope there. They'll be sending people to the dark side anyway to deal with the nuclear waste dump there. Unfortunately, we'll lose both when an accident at the dump turns it into a giant rocket and propels the Moon out of the solar system.

jeanlou• 3 years ago

"Alleged dark" matter he should have said. He haven't been able to detect it up to now.

Out_of_Characte• 3 years ago

Dark matter has a very simple and literal explanation, matter affected by gravity (thus below the speed of light) that we arent able to detect. This could be almost entirely mundane things like planets of asteroids that are impossible to see at lightyears if they dont pass in front of a star.

Dark energy is the odd one that is part observation, part speculation

z3phyr• 3 years ago

In our Solar System, planets, dwarf planets, asteroids, space dust together hold 0.15% mass. The rest of the 99.85% mass is held by the Sun. I think this mass distribution is uniformly true for other stellar systems as well, where majority of the mass is held by the stars (singular, binary, collapsed) and very small amount by other objects in the system.

Given the above, why is there so much postulated "dark matter"?

ggm• 3 years ago

If you want to watch a fight, Get Astronomers into the room with "manned space in LEO is important because..." people and say "robots work in space"

Actually you can probably get the same outcome by putting land optical scope astro people up against space optical or RF people. "all that launch cost spent on active optics here on the ground could.."

DiogenesKynikos2• 3 years ago

There's not really a conflict between land- and space-based telescopes. They have very different capabilities. There are things you can only do from space, and things you can only do from the ground.

To give you an example, using adaptive optics, you can get higher resolution on small fields of view from the ground. That's because you can build much larger telescopes on the ground, which therefore have a smaller diffraction limit, and you can use adaptive optics to correct for the atmosphere in a small field of view. However, if you want high resolution over a large field of view, you have to go to space.

Other advantages of space: extremely stable calibration (because you can control conditions more precisely, and because there's no atmosphere) and ability to view parts of the spectrum that are unavailable from the ground.

Other advantages of ground-based telescopes: larger and heavier instruments, ability to do repairs and upgrades.

Robots vs. manned spaceflight is much simpler. Robots will almost always give you more science return for the same price. I still think manned spaceflight should be pursued, but for other reasons (it's cool, and we should be pushing the envelope of what's possible).

moi2388• 3 years ago

Right. I suggest astrophysicists first start using Einstein instead of Newtons theory of gravity, and actually use Pi instead of 3, etc. Before they ever have the right to complain about wanting more accurate devices :p

boffinAudio• 3 years ago

There already are 'telescopes' on the moon .. in the form of the Hasselblad [1] cameras that were left on the rover passenger seats, pointed up into the cosmos, for future retrieval ..

No doubt some physicists of the future are going to be very interested in the contents of those lenses. Kind of the "pitch drop experiment" of astrophysics, I suppose.

[1] https://www.hasselblad.com/about/history/hasselblad-in-space...

Building telescopes on the Moon could transform astronomy

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