How To Build a Telescope That Trumps Hubble

An anonymous reader writes "In cleanrooms around the country NASA and its contractors are building the James Webb Space Telescope, a marvel of engineering scheduled to launch in 2014. This gallery shows the features that will allow Webb to take the universe's baby pictures in infrared — most notably an 18-segment mirror and a 5-layer sunshield. I can't wait until Webb settles into its Lagrangian point way out beyond the moon and gets to work."

Comments

The universe is infinite

[ubergeek65536]

So why do they thing that the universe isn't infinite? It seems that every time they get a bigger telescope the size of the universe gets bigger :\ Did they ever think that that big bang thing could have just been a localized event?

Re:The universe is infinite

[dkleinsc]

Why do you think it is infinite, without any proof whatsoever? All evidence we have is that the observable universe is finite, and observations of the early universe (thanks to the finite speed of light) match what the Big Bang Theory predicted. Ergo, it's the best answer we've got right now, and the burden of proof is on those who have evidence to the contrary to produce it.

Is it possible there's an unobservable universe outside of the observable universe? Of course. But you can't do science with it because it is simply impossible to observe.

Re:The universe is infinite

[ubergeek65536]

I have just as much proof that the universe is infinite as they do that it's not. That is to say exactly none. We will never be able to prove that it is infinite by measurement just and we will never be able to prove that it is finite. Like I said a hunch isn't exactly proof with either argument. A year ago the "universe" was about ten times smaller than it is now. Once the new telescope is functional I'm going to make the wild speculation that to will get bigger yet.

Re:The universe is infinite

[fishbowl]

Was space created by the Big Bang, or did the Big Bang happen inside of space that already existed?

Observe something that is more distant in space-time than the big bang, and settle the matter!

It is fine to speculate, but if you want coherent scientific models of the universe, you need to either assume the 13.7 billion light-year horizon or else show by observation or by theory that the horizon does not exist.

The ideas of an infinite theoretical universe aren't incompatible with a finite observable universe, but people who build telescopes are going to be concerned exclusively with the practical aspects of the latter, even if they believe in the former.

Re:The universe is infinite

[Zorpheus]

We can not see further than 13.75 billion light years because this is the distance that the light has travelled since the universe has become transparent. This happened 300,000 years after the big bang.
It does not really matter if it is infinite or not.

Re:The universe is infinite

[bunratty]

I don't understand this idea you have that the amount of the universe we can observe is getting bigger. Since the 1960s, we've observed the cosmic background radiation. It's the thing farthest away we can observe, because before the cosmic background radiation became visible the universe was opaque. We have been able to resolve galaxies that are farther and farther away, but we knew that there was universe there. We just weren't able to see physical, gravitationally bound objects there before.

Re:The universe is infinite

[Nemyst]

You really don't know much do you? The radiation comes from the beginning of the universe, back when everything was a huge soup of particles. It's one of the greater proofs for the big bang theory, since there's no other reason for it to be there than to have one point where the universe was so dense it was irradiating in a nearly uniform manner. By studying the irregularities in the emissions, we can then learn more about that state in the universe's evolution, as well as what happened after that.

There's no distance to speak of because when those were around, they were everywhere and the universe wasn't of the same dimensions. We can measure that the universe is expanding, the big bang theory says there was a time where it was essentially a singularity, thus we can say (with good probability of being right) that the universe is finite.

Is it finite in the sense of a sheet of paper? Probably not. There won't be a wall with "the Universe ends here." written on it. Rather, it might very well be like the flat Earth theories: a loop that uses an additional dimension to complete. Whereas the Earth is a 3D object that was being represented as 2D (so you'd have edges even though they do not actually exist), it's very possible the universe loops around in another higher dimension.

Re:The universe is infinite

[bunratty]

You sound like Bill O'Reilly. Cosmic background radiation. You can't explain that.

Your argument is just like the arguments of people who disagree with evolution or AGW. You're just making stuff up to be argumentative. If you actually want to learn something, you can read about it.

Re:The universe is infinite

[stevelinton]

We have seen ligth (actually microwaves) from events longer ago and so more distant in space than the early galaxies Webb is targetting -- namely the cosmic microwave background. However there is a gap between that, and the most distant objects we can see in detail with Hubble. Webb is to look into that gap.

Re:The universe is infinite

[khallow]

I did state that the near uniform radiation may only appear to be uniform because we lack the method to measure it with greater precision.

We already know that the cosmic microwave background (CMB) is near uniform not uniform. The perturbations in the CMB have been measured and are one of the attempts to say things about the parts of the universe that we can't observe (not being in our light cone), such as a minimum estimated extent of the current universe.

Re:The universe is infinite

[bunratty]

Science doesn't even attempt to prove things. The best science can do is find a model that works. If you want proofs, do mathematics. If you actually want to learn about how science is done and what science is all about, you can read about it.

Re:The universe is infinite

[jo_ham]

Who says you can't be skeptical about AGW? That's never been the argument.

The reason it appears so is because there is a vast imbalance in the two "sides" of the AGW debate regarding scientific knowledge and understanding of the way science works. On the one side you have actual scientists, on the other side you have people (often high profile TV and radio hosts) where the level of scepticism is on the order of "well, look at all that record snowfall we had last night! so much for this so-called "global warming" eh?!"

There's a difference calling out that sort of "contra evidence" as rubbish and pointing at the large propaganda machines that fund the anti-AGW movements. The weight of politics in the debate is far, far swung to the one side (but it clearly not absent from the other side). A large number of skeptics are asking to be weighted at an equal level to that of professional scientists when they really have no business or expertise in that field. It's all very well "offering the other side's point of view" - just because these non-science detractors, or those who haven't even looked at the evidence but still argue against it on "common sense" arguments (like 'the earth is so big, there's no way we could be affecting its climate') or who demonstrate their knowledge of science is shaky at best (the moon! you can't explain that!).

Science is all about listening to skeptics. Challenging your model is the way you make it better so that we *can* explain those gaps, or look at areas we didn't understand before with fresh eyes and different ideas. That has never been in dispute, and actual climate scientists (and others who work closely in the field like physical chemists and spectroscopy experts whose areas of study are not just confined to the Earth's atmosphere or atmospheres in general) have never worked from a platform of "you're not allowed to criticise us". In that respect it is no different from any other area of science. The only difference is that it has a serious amount of political and commercial baggage attached to it, with a large number of special interest groups who are not pleased that the science seems to be telling them things that are not profitable or politically convenient to hear.

If you (the general you) have any scientific criticism of the models used in the AGW and climate change in general, then scientists want to know - it's an area of interest that has been refined over decades, and is getting better all the time. You (again, the general you) might want to start from the generally accepted model that increased CO2 in the atmosphere absorbs IR, and that the mean average temperature has gone up, and if you fill a greenhouse with steadily higher partial pressures of CO2 and measure the effect on the temperature the results are clear. Add to that the fact that the CO2 concentration has jumped far, far above the highest level it has ever been in 600,000 years and you have to conclude that humans are *likely* to be responsible for that. If there is another model that explains it that can stand up to scientific review then they are open to hearing it.

The trouble is, much of the criticism is aimed at the scientists themselves, or just doesn't understand the data that is presented - science has always had an image problem, especially in conveying results to ley people, and this weakness has been expertly exploited by those with an agenda to push.

How To Build a Telescope That Trumps Hubble

[Anonymous Coward]

Put a bad toupee on a telescope.

Budget Cuts and the JWT

[Petersko]

The budget cuts announced by Obama include cutting $64 million from the James Webb Telescope program, "which an indendent group of experts "found to have a fundamentally broken estimate of cost and schedule".

While I recognize the U.S. is totally fucked, economically, this is a mistake. Throwing a minor budget item with huge potential like this under the bus in the name of pretending to become fiscally responsible is beyond short-sighted.

Re:Budget Cuts and the JWT

[DisownedSky]

A 64 million dollar cut isn't much at JWST's burn rate. It's not being thrown under the bus at all. In fact, it's eaten all the money intended for other, equally worthy space science mission. Realistically, it isn't going to launch until 2015 at the earliest (my money's on 2016) and will cost much more than it's current massive overrun.

Re:Budget Cuts and the JWT

[dkleinsc]

While I recognize the U.S. is totally fucked, economically, this is a mistake. Throwing a minor budget item with huge potential like this under the bus in the name of pretending to become fiscally responsible is beyond short-sighted.

The reason that's happened is that the US is totally fucked politically as well as economically.

I hope they're building several of these

[PeterM from Berkeley]

I think just having "one" Hubble space telescope was a mistake. I hope they're building more than one of these new 'scopes.

I mean, it'd be a shame if a launch incident destroyed a unique capability. And it shouldn't cost anything like N times as much to build N of these at the same time, right?

--PM

Re:I hope they're building several of these

[Anonymous Coward]

Of course not - the thing is a few billion Dollars to build and not exactly cheap to launch either.

In fact - if it does break, even if just in a minor way (e.g. the solar panels don't unfold because a space flea is jamming a gear), it's likely going to be a multi-billion dollar piece of space junk.
Why? Because it's going to sit at the Lagrange 2 point when it goes operational. That's far, far further than we've put humans (way beyond the Moon), which so far have been the only instruments adapt enough to do repairs on satellites (such as the ones for Hubble).

As it is, the James Webb Space Telescope is awesome - in infrared and -only- infrared. People suggesting it's a -replacement- for Hubble (IR, Visible, UV) are completely and utterly deluded.. or looking for additional grant money. They might as well claim it's a replacement for Chandra (X-Ray) as it's almost equally as idiotic.

Re:I hope they're building several of these

[spacemandave]

Actually, more than a dozen "Hubble space telescopes" were built and launched into orbit. The biggest differences are that they point at the Earth instead of away from it, and they are called KH-11 instead of HST. Oh, and their imagery data is mostly classified.

Re:I hope they're building several of these

[spacemandave]

http://en.wikipedia.org/wiki/KH-11_Kennan

Look at the price tag

[PineGreen]

As a professional astronomer I hoped this thing would never have happened. It costs 6 billion and at this price tag a 5% overrun is $300 million, about six times the cost of the entire SDSS project, which has undoubtedly gave us more science that James Webb ever will. True, Hubble and JWST make great pictures, function as amazing PR machines, but most science at the end of the day comes from survey imaging and spectroscopic observations.

Re:Look at the price tag

[JoeMerchant]

SDSS was good science, making great use of relatively humble tools. But, it takes an ecosystem - and heavyweight instruments like the Webb, or the LHC, will illuminate things that can later be confirmed with the broader toolset of more pedestrian instruments, things that would just be considered a wild theory unless they came with backing from observations on an instrument like the Webb.

You also need to face up to the reality that if the Webb were scrapped at inception, it wouldn't have meant $6B extra would have been supplied to general astronomy, only a small fraction of that money would have made its way around the community.

Re:Look at the price tag

[melikamp]

I totally believe you when you say that surveys provide more and better scientific data, but as a tax-payer I am thrilled with HST's performance, and I could hardly be happier about this wealth of data, which is useful to everyone, professionals and amateurs alike. The only thing I dislike about JWST is that we cannot service it, as so we miss an opportunity to launch more people into space. You guys could turn the surveys into PR machines too, you know. In KStars, for example, there are shortcuts to download DSS and SDSS. I click on the star map and a DSS picture for that place gets pulled. But it could be so much better: DSS is slow to the point of being unusable, and the available SDSS data doesn't seem capture that much of the sky. With a bit of tweaking, I bet we could have a google-map-like app for the surveys to blow everyone's mind, and then you'll see more cash pouring in for these kinds of projects.

Re:Look at the price tag

[DerekLyons]

As a professional astronomer I hoped this thing would never have happened. It costs 6 billion and at this price tag a 5% overrun is $300 million, about six times the cost of the entire SDSS project, which has undoubtedly gave us more science that James Webb ever will.

Science isn't something you can measure by how many buckets you collect. Not all buckets have the same value.
 

True, Hubble and JWST make great pictures, function as amazing PR machines, but most science at the end of the day comes from survey imaging and spectroscopic observations.

If you honestly believe that all Hubble and JWST are doing or will do is collect pretty pictures, you're either hopelessly ignorant or hopelessly biased. But ff you want to talk spectroscopy - consider that four of the Hubble five main instruments are dedicated to spectroscopy, and two of JWST's three main instruments are so dedicated. If you want to talk surveys... Check out Hubble's schedule from Feb 14, 2011, or January 29, 2011 for some recent survey campaigns that Hubble is participating in.

There is no "do over" for James Webb

[Just_Say_Duhhh]

Not that I'm expecting some catastrophic screw-up on the scale of the Hubble, but if there is a problem with the JWST, once it is sitting out at the Earth-sun L2, we won't be able to go visit it and repair it. I haven't heard of any contingency to allow it to come back to earth, so they've really got one shot to get it right.

I'm hoping everything is nominal.

Re:Teaser title!

[natehoy]

Meaning no offense, but have you ever actually submitted a story? Titles are limited to 50 characters. It leads to terrible, terrible headlines.

"How Scientists are Building a Telescope That Trumps Hubble!" gets truncated to "How Scientists are Building a Telescope That Trump"

Many of the bad headlines here are actually the result of trying to get something like "How scientists are building a telescope that is superior to Hubble" in a headline field that basically only allows "Science cool! They build'um Hubbleplus Telescope!" (note that, coincidentally, my headline just happens to fit with ZERO extra spaces.)

Re:Why such a high orbit?

[AikonMGB]

JWST's optics and sensors have to be kept very cold, something that is difficult to do in LEO thanks to all of the Earth IR and albedo. Putting it at L2 means the Earth's disturbances will be in line with the Sun's, and they can use a single stationary shield to protect the optics and sensors.

But yes, you are right, it will be significantly more difficult (impossible with current technology) to service it.

Aikon-

"trumps Hubble"

[Lemmy Caution]

OK, I have no productive contribution here, but the phrases "Hubble trumping" and "trouble humping" are now echoing through my head.

Re:Are La Grange points safe for satellites?

[rcw-home]

The L2 point (which is where JWST is headed) isn't a gravity pit - it's a gravity hill. It's a long-term unstable orbit, but it takes minimal delta-V to stay put there with active correction.

L4 and L5 (60 degrees ahead and behind the orbit of the lighter-mass object) are the gravity pits, and lots of miscellaneous stuff does collect there. But even then, it's still nearly empty space and whatever has collected there isn't moving fast relative to you.