Space Telescopes Vs Particle Accelerators?

RobotWisdom asks: "As I follow the scientific results from the Hubble and other space telescopes, it sure seems like they're delivering a ton more bang-for-the-buck than particle accelerators could ever dream of. If we can map the universe at every wavelength, won't this be data enough to -deduce- the particle laws? Is there still any reason to waste any money on accelerators?"

No

[gwalla]

If we can map the universe at every wavelength, won't this be data enough to -deduce- the particle laws?

Nope. Deducing particle laws from this sort of data would be very indirect, especially because there could be other unexplained factors. It's still a good idea to be able to perform experiments under controlled conditions.

Also understand that most of the large particle accelerator projects have a hard time getting funding. Remember the Superconducting Supercollider? It may be true that existing particle accelerators have done their work, but particle accelerators in general have a long way to go.

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Zardoz has spoken!

Telescopes vs. Accelerators

[Detritus]

If we can map the universe at every wavelength, won't this be data enough to deduce the particle laws? Is there still any reason to waste any money on accelerators?

Your name and address has been forwarded to the American Physical Society [aps.org] :-).

You need both. Telescopes tell you about the behavior of large collections of atoms. Accelerators tell you about the behavior of individual atoms and particles. If you are interested in how stars evolve, you need to know the behavior of atoms on both the large and small scale.

I was just reading a book that pointed out the fact that Earth based neutrino detectors only detect about 1/3 as many neutrinos as predicted by our models of the Sun. Is the Sun running cooler than predicted by the models, or is our understanding of the neutrino incorrect?

Photons are all

[mustermark]

we get with observatories. (And to some extent neutrinos.) Only one force in nature is transmitted by photons (the electromagnetic force), so there's a lot we're missing. Astronomical objects are by nature very far away and uncontrolled. Anything could be happening that you don't see. Also, there is no opportunity to see very high energy phenomena. The latest colliders can make a quark-gluon plasma [starstuff.org]. When's the last time you heard of an astronomer seeing that? These exotic particles and matter like this are short-lived, so their properties are almost impossible to infer from astronomical observations, which take many years to reach us.

Another point is that most astronomers deduce the physics by comparing observations to known physics. We see spectral lines in stars and know that they signify certain elements because we can reproduce the spectral lines of a single element here on earth and compare.

Moral: Ug like collider too. Make happy.

Re:Photons are NOT all

[tjwhaynes]

IWAA (I was an Astronomer) :-)

Astronomical objects are by nature very far away and uncontrolled. Anything could be happening that you don't see.

It's certainly true that Astronomers have no control over the processes they watch - however, there is choice over what you watch. Part of the art of astronomy is learning how to pick up the threads of other observations to determine what to look at next.

Also, there is no opportunity to see very high energy phenomena.

I blinked a bit when I saw this. Or maybe your definition of high energy phenomena is a little higher than mine. I'd put intracluster (i.e. clusters of galaxies) gas at 10^9K as being a high energy plasma, along side supernovae, neutron stars, quasars, molecular outflows (from stars), black holes and gamma ray bursts as all belonging to the high energy phenomena bracket. There are plenty of others - without high energy phenomena the astronomers would be out of a job.

The latest colliders can make a quark-gluon plasma. When's the last time you heard of an astronomer seeing that?

What are it's macro properties? [Ed - glib comment alert!] If you can tell me that, I can probably find some astronomers who'll look for it.

These exotic particles and matter like this are short-lived, so their properties are almost impossible to infer from astronomical observations, which take many years to reach us.

Well - true up to a point. Astronomical observations do take a long time to reach us. But because space is not a particularly dispersive media the signal received still maintains much of its time resolution without distortion. Even fast changing properties can be observed - take for example millisecond pulsars. However, if you are talking about low energy events which occur in localised regions or which are easily masked by surrounding gas/dust, then you won't see these.

Comparing Astronomical observations and Particle Physics observations is useful up to a point. Astronomy relies on many parts of modern physics to interpret the data received, and if you cut off funding to one part of physics, you are almost certainly imparing the understanding of other parts of physics as well. Part of the problem that Particle Physics has is that it has a limited store of pretty pictures that can be trotted out to the general public. Astronomy has never has this problem - as telescope technologies have pushed ever on, we've discovered that the multitude of phenomena out there make extremely good posters as well as providing us with a deeper understanding of the universe. So I suspect that Particle Physics is almost certainly giving us bang-for-the-buck - the problem is that much of that information is too technical for most people to understand and that there are only limited opportunities for news-worthy items for the general public. So you tend to miss out on it.

Cheers,

Toby Haynes

Don't forget PR

[hubie]

Your perception of space telescopes vs particle accelerators is probably affected by the amount of press NASA provides. NASA has (for many reasons) a very good PR machine and they do a very good job of getting beautiful pictures out to the public. Fermilab, CERN, etc. also cranks out a lot of good stuff, but it isn't the kind of thing that is going to make the evening news or the cover of popular magazines.

Additionally, it also depends on your perspective. Particle accelerators have done much more to advance our understanding of the physical laws than telescopes (or most other instruments). On the other hand, nothing has given us a better sense of the grandeur of the Universe and our part in it than telescopes. There are probably more "gee-wiz" discoveries to be made by telescopes because we have only recently been able to escape the bounds of our atmosphere which has opened up a whole new realm of wavelengths to our eyes. However, particle accelerators have already made all the easy discoveries and they are now probing the heart and soul of the physical laws.

It is a very exciting time for either field.

Did I hear you correctly?!

[Anonymous Coward]

We definately need both. There is a lot of reasons for this, of which some of them have been o utlined. Such as the fact that telescopes only measure stuff on really large scales, while particle colliders give direct readings on small scales. Also, EM radiation is one of 4 forces. We can infer some gravitational stuff by looking at the motion of galaxies (but this is hard), but the strong and weak force would be almost impossible to deduce from astronomical data (although it does play a lot in figuring out stellar evolution). Particle accelerators give data on all these forces. Good, solid, direct data, that gives us insane amounts of accuracy. Furthermore, particle accelerators can push energy levels up to levels that only the early universe was in... back before the universe was opaque to photons. what this means, pratically speaking, is that high energy phenomona is forever hidden from us behind the background radiation. Therefore, the only way to observe it, is to recreate it ourselves, in colliders. By doing this, we have discovered particles which we would never had dreamt of. And as we press colliders to higher energy, we'll probably be in for more suprises. I have a feeling that the particles we have seen so far, are just the low energy ones, and that many more exist at higher energies. Anyway, as a physics student, I couldn't let this by without a comment. Hope I was of some help. -Anonymous Coward -> Too Lazy to Make an Account

Re:Don't forget PR

[KjetilK]

I agree with your point that it has a lot to do with PR. I also agree that we most certainly need both, BUT

Particle accelerators have done much more to advance our understanding of the physical laws than telescopes (or most other instruments).

I can't agree with you here. I claim that the telescope is the single instrument that has historically advanced our physical understanding the most. Mostly because of Galileo and Kepler, it started a new way of thinking in causal processes. Now, particle accelerators, from Rutherford to today has indeed done a lot of nice work, that has overthrown many theories, and confirmed many theories. So have telescopes. Take the expanding universe for example. Neither have, lately, provided a kick for a real scientific revolution, though, so I think they are pretty equal in merit in this century. And, who would like to guess in what direction the next revolution will be? We won't know untill we are there...

Re:YMHBAA, YCWNAEM

[mustermark]

(You Must Have Been An Astronomer, You Certainly Were Not An English Major.)

And neither were you -- this is a comma splice.

Re:Photons are NOT all

[mustermark]

Well, I *am* an astronomer. :-)

It's certainly true that Astronomers have no control over the processes they watch - however, there is choice over what you watch. Part of the art of astronomy is learning how to pick up the threads of other observations to determine what to look at next.

That is not even what I was talking about. I mean you have no way of separating physical phenomena, i.e. interstellar effects vs. a peculiar spectrum. That makes quantitative analysis difficult. Ask any astronomer about the distance to the LMC. Ha!

blinked a bit when I saw this. Or maybe your definition of high energy phenomena is a little higher than mine. I'd put intracluster (i.e. clusters of galaxies) gas at 10^9K as being a high energy plasma, along side supernovae, neutron stars, quasars, molecular outflows (from stars), black holes and gamma ray bursts as all belonging to the high energy phenomena bracket. There are plenty of others - without high energy phenomena the astronomers would be out of a job.

Again you are off the mark. These are energetic macro phenomena. A supernova has 10^51 ergs behind it, but individual particle energies are not too remarkable. The closest astronomers come to something I would call cool is high energy cosmic rays at 10^20 eV per particle. We could observe them with the right equipment, but right now we're stuck with watching the showers of particles they create when they smash into our atmosphere. Even so, they are too rare to do much with and not directional, since they are affected by galactic magnetic fields.

What are it's macro properties? [Ed - glib comment alert!] If you can tell me that, I can probably find some astronomers who'll look for it.

That's the point. Some things may not have macro properties. What then?

Well - true up to a point. Astronomical observations do take a long time to reach us. But because space is not a particularly dispersive media the signal received still maintains much of its time resolution without distortion.

Again you miss the point. These high energy interactions in particle colliders create particles with very short lifetimes, so they would decay before reaching Earth. Thus, we get no kaons, pions, etc., from supernovae. Not to mention they'd take longer to get here. The way to determine that they're being created is look for their macro signatures in colliders on earth and then compare with astronomical observations.

How can you people moderate this stuff up?