Chandra Getting Results

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 06:25 · Score: 0

Yes, you are a worthless toad who should be shot immediately.

Your life is what you make it. There are many people who have made a large impact on our small planet, whether positive or negative. That seems to be the best you can hope for now. The galaxy will have to wait.

Re:Black Holes by Anonymous Coward · 2000-01-15 06:27 · Score: 0

I'm not a scientist, but I bug my friends by acting like one.

I don't think you'll have anything to worry about, for two reasons:

I don't think black holes "grow", at most very little if at all.
Like you said, in a billion years we will all be dead. :-)

Re:3 Questions by Anonymous Coward · 2000-01-15 17:05 · Score: 0

1.) If there were a Big Bang that everything exploded from, why are we not substantially closer to one side of the background than the other?

Because in relativity theory, everyone (well every fundamental observor) is entitled to consider themselves to be at the centre of the Universe. Basically, if there's no special reference frame, everyone must be at the centre of their own frame.

2.) X-rays are just another wavelength on the electromagnetic spectrum, right? What says that a wavelength can't get changed in the course of its travels across the universe?

They do. The X-rays will have been redshifted, from harder X-rays (possibly even gamma rays, depending what their redshift it). Looking at the spectrum, you will see absorption lines from intervening matter. In part, it's identifying these lines that lets you work out how far away something is - if it's light has passed through object A, then it must be further away.

Remember that the microwave background was towards the ultraviolet when it was actually emitted (I don't know the exact waveband, since the exact calculation is rather tricky).

3.) If we really are seeing 14 billion years into the past, and this represents something close to the beginning of the universe, why are we seeing galaxies?

I think the answer is, we don't know the exact age of the universe. This is because we can't be sure which cosmological model is correct (the Hubble constant is one of the better known cosmological parameters, and that's only been recently pinned down to better than a factor of two). So we're not too sure how old the universe. If it's actually about 20 Gyr, then galaxies at 14 Gyr are not unreasonable.

Re:Is this news? by Anonymous Coward · 2000-01-16 00:09 · Score: 0

In addition to what others have said, remember that the whole universe radiates as a blackbody. The universe has an average temperature that depends on the amount of energy released in the big bang and the current size of the universe. As the universe expands, it cools. Blackbody radiation is distributed throughout the frequency spectrum, but its peak is determined by the temperature. So the peak of the cosmic background radiation spectrum moves to lower frequencies as the universe expands and cools. Currently the peak is in the microwave portion of the spectrum. Also, the background radiation is not quite uniform. Experiments conducted in the early '90s with a special purpose microwave telescope showed that the background radiation is uneven, indicating that the initial expansion of the universe after the big bang was also slightly uneven. The amount of cosmic background radiation (blackbody) in the X ray bands is very, very small. The X ray background discussed in this article is mostly unrelated to the cosmic background radiation.

Re:Is this news? by Anonymous Coward · 2000-01-16 00:13 · Score: 0

(sigh)
No, it isn't that either.

The distribution of cosmic background radiation in the spectrum follows the laws for a blackbody radiator. The peak of the radiation spectrum is determined by the average temperature of the universe (which is slowly decreasing). There is no doppler shifting involved.

Re:this post is offtopic... by Anonymous Coward · 2000-01-15 06:28 · Score: 0

I don't beleive that somebody screwed this up and marked it as a "Troll".

Re:X-Rays... by Anonymous Coward · 2000-01-15 06:28 · Score: 0

uhhhh i was not aware there is any x-ray sheilding on TV's. mabye im wrong do you have a link or something that coroborates? i would like to find out more

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 06:34 · Score: 0

My point was not one of nihilistic despair (which you obviously mistook it for), but one of how stupid for example the race to gain huge amounts of wealth and/or power really is.

Re:X-Rays... by Anonymous Coward · 2000-01-15 06:41 · Score: 0

The accretion disk around the black hole (basically a whopping mass of crushed up matter) is the key. Matter in this disk gets extremley hot, and releases X-Ray radiation, amongst others.

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 06:42 · Score: 0

Y'know, most people get over this by age 16 or so.

Re:X-rays can beat black hole gravity? by Anonymous Coward · 2000-01-15 06:42 · Score: 0

This radiation isn't in the form of X-Rays, but actually fundemental particles (Pairs of quarks i.e. protons and neutrons). This is known as "Hawking radiation" after Stephen Hawking, the guy who first theorized it.

Re:How did they calculated... by Anonymous Coward · 2000-01-16 02:28 · Score: 0

Actually, the redshift is multiplied by the speed of light, then divided by Hubble's constant: cz = Hd, where c is the speed of light, z is the redshift, H is the Hubble constant & d is the distance being calculated. And emission or absorption lines can found across the entire EM spectrum...an object does not need to be emitting in the visible region in order for its redshift to be found.

Postmodern Physics: Liberal Academic Gibberish by Anonymous Coward · 2000-01-16 03:13 · Score: 0

I want to thank you for bringing the situation to our attention. Every time you turn around, they're up to something new; nobody can keep a watch on the whole government by himself. Only by sharing information like this can we stay well-informed.

Anyhow, here's a thought I just had: Have you ever noticed that the jargon of Liberal so-called "Big Science" is effectively identical to the equally nonsensical jargon of so-called "Postmodern" (i.e. homolesbian/feminazi/Marxist) Literary Criticism? It's all just a bunch of ten-dollar words thrown together at random! It seems obvious that the same forces are at work.

And it's not just science and the arts, either. They've even infiltrated the field of computers. Here's one that I found. It's a pathetic attempt at intimidating decent, honest Americans who (since they're decent and honest) aren't members of the Liberal East-Coast Elite:

When left recursion is eliminated from this translation scheme, nonterminal E corresponds to A in (5.2) and the strings +T and -T in the first two productions correspond to Y; nonterminal T in the third production corresponds to X.

Aho, Sethi, and Ullman: Compilers: Principles, Techniques, and Tools, p305.

Now, I don't know about you, but I can read and I'm not an ignorant man. If I pick up a book and open it in the middle, I expect to be able to read a page or two and know what the hell is going on in it. Let's face it, if you can't explain your subject to a non-expert, you really don't understand it at all. Jargon is the last refuge of the incompetent! Well, here I think we have a perfect example. Hell, I even tried starting at the beginning of that laughable farce of a book, and it still didn't make any damn sense!

The funny thing is, those guys that wrote that book probably think they got away with it. And what's even funnier is the fact that you could probably walk into any college in the country and find a few computer "science" students who would pretend that they could understand it! Boy, these liberals sure are a piece of work.

Re:Postmodern Physics: Liberal Academic Gibberish by Anonymous Coward · 2000-01-16 04:21 · Score: 0

When left recursion is eliminated from this translation scheme, nonterminal E corresponds to A in (5.2) and the strings +T and -T in the first two productions correspond to Y; nonterminal T in the third production corresponds to X.

Ye gods! That's the Dragon book, isn't it? Yes, I am quite familiar with this piece of socalist trash. We discussed it at a church prayer meeting last month. The symbolism is sickeningly blatant. Dragons shoot fire, which is usually depicted as being quite flaming. This is a clear reference to homosexuality, and is a prime example of how these liberal monsters will stop at nothing to promote their agenda of multiculturalism whenever they have an opportunity.

You're right about the jargon, though. Somewhere deep within the bowels of Liberal Headquarters at Berkeley, the liberals have several high-power computers (most likely Macintosh G4s) that do nothing but crank out liberal buzzword jargon phrases day in and day out. For example, they might generate the phrase "LR(1) grammar" and use it in a textbook. Now you and I know that "LR" stands for "Lesbian Russian", and that it is a clear attempt to promote the liberal causes of lesbianism and Communism. We just have to make sure the rest of the world knows, as well.

These monsters must be stopped.

X-Rays... by Anonymous Coward · 2000-01-15 05:23 · Score: 0

How exactly does gas being pulled into a blackhole produce an x-ray? and how are x-rays produced here on earth for imaging etc?

-esobofh

Re:X-Rays... by Anonymous Coward · 2000-01-15 07:15 · Score: 0

hmm! interesting! i wonder what the electron beam is accelerated to in the CRT, i must be wrong about it being around a few EV.
Re:X-Rays... by Anonymous Coward · 2000-01-15 06:23 · Score: 0

television cathode ray tubes do not create X-rays b/c the electrons are only accelerated to a few elevtron volts---not enough to force x out of the phosphors and the screen/mask in the front.
Re:X-Rays... by Anonymous Coward · 2000-01-15 06:40 · Score: 1

> How exactly does gas being pulled into a
> blackhole produce an x-ray? and how are x-rays > produced here on earth for imaging
> etc?

Easy! We take really big trash compactors and smush down all those AOL floppies,CDs, and old National Geographics in our basement, stir in some MakeMoneyFast emails and mash 'em down even more until they form eensy-weensy little black holes, then dump gas into them to make X-Rays. In fact, next time you go to the dentist, ask them if you can open up the X-ray machine and play with the black hole inside. (If they offer you a complimentary somewhat-oversized white jacket, politely decline and run like hell!)
Re:X-Rays... by Anonymous Coward · 2000-01-15 07:16 · Score: 1

Black holes only produce X-rays when there is matter flowing into them. That's usually not a problem, since black holes are pretty good at attracting matter :)
I believe that when gases are compressed down to that level, near the event horizon, the gas gets so hot that high-frequency gamma rays are emitted. Relativity does its thing, and you have x-rays (longer wavelength than gamma) once you get far enough out of the black hole's gravity field.
Now, there's an entirely different kind of radiation that's been theorized, Hawking radiation, which says that even a black hole with no matter flowing into it can emit radiation.
Quantum theory states that matter-antimatter particle pairs are spontaneously bursting into existence from the vacuum, and this happens constantly. Normally they just annihilate each other immediately. But when a particle pair pops into existence too close to the event horizon, one particle may get sucked in before the annihilation, and the other flees into outer space, and so it appears that the black hole is "emitting" particles. This is probably a half-assed way of stating the theory, but you get the point.
Re:X-Rays... by DGolden · 2000-01-15 06:48 · Score: 1

It is true - certain TV sets used to give out quite a bit of X-Ray radiation. Modern TVs + computer VDUs are built to minimise leakage.

www.tiac.net/users/shansen/belljar/xray.htm
The paragraph towards the end is the relevant bit

--
Choice of masters is not freedom.
Re:X-Rays... by Tony-A · 2000-01-15 08:04 · Score: 1

by a few orders of magnitude.
Color TV is 25,000 volts IIRC.
B&W TV is about 17,000 or 18,000 volts.
The X-Radiation is rather weak, almost negligible for B&W, but strong enough on color that you do not want to be right on top of it.
Re:X-Rays... by Voltage_Gate · 2000-01-15 23:56 · Score: 1

So something in the atmosphere shields the earth from X-rays, as a plate of glass does the same on a television... how close can I get to the TV if Baywatch is on? Should I add another layer of glass? Is there a standard material that they use to protect astronaughts? Lead must be expensive to hoist into orbit.
Re:X-Rays... by Relforn · 2000-01-15 09:02 · Score: 1

In some of the older tube-type color TV sets that I used to work on for fun and troubleshooting experience, the high voltage rectifier tube was even wrapped in a lead-composite shield over the glass envelope.

The X-ray emissions of a CRT can be increased to hazardous levels in some cases simply by tweaking the high voltage to out-of-rating levels. Overdriving some color monitors can do this as well. You don't notice anything right away, because cataracts are long term eye damage.
Re:X-Rays... by JustShootMe · 2000-01-15 06:43 · Score: 1

http://www.mathematik. uni-marburg.de/~kronjaeg/hv/hv/do/crt/
If you can't figure out how to mail me, don't.

--
For linux tips: http://www.linuxtipsblog.com
Re:X-Rays... by JustShootMe · 2000-01-15 15:59 · Score: 1

I believe old color TV sets can reach up to 40,000 volts.

If you can't figure out how to mail me, don't.

--
For linux tips: http://www.linuxtipsblog.com
Re:X-Rays... by JustShootMe · 2000-01-15 06:24 · Score: 1

This is not true, otherwise there would not need to be X-ray shielding on televisions. I know, I used to open them up and work on them.

Maybe they're not very powerful but they *do* exist.

If you can't figure out how to mail me, don't.

--
For linux tips: http://www.linuxtipsblog.com
Re:X-Rays... by JustShootMe · 2000-01-15 05:49 · Score: 2

X-rays are produced here by accelerating electrons to very high speed and smashing them against a target. Kinda like a miniature acelerator, I think. That's why televisions create x-rays, because the tube is essentially a low-energy particle accelerator, smashing the electrons against the phosphor of the screen and making them glow.

I'm not one hundred percent sure of how the black holes create them, but I think it has something to do with the kinetic energy of the electrons as they fall over the event horizon... someone feel free to correct me.

If you can't figure out how to mail me, don't.

--
For linux tips: http://www.linuxtipsblog.com

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 06:47 · Score: 0

oops, sorry then.
i guess i'll have to burn the motivational picture of a smiling RHAT stockholder that I was going to send you.

how existential. (sp)

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 06:48 · Score: 0

Doh!! :-)

Re:BUT CAN IT... by Anonymous Coward · 2000-01-15 06:49 · Score: 0

Does this mean that we can't be sure that Hemos is always wearing pants?

That's a gruesome thought...

Re:Black Holes by Anonymous Coward · 2000-01-15 06:50 · Score: 0

Or the hole evaporates by Hawking radiation

(which is what is most likely to happen to the small one 1600 light years away)

N.B. Hawking Radiation is a mechanism whereby a black hole loses energy by eating only one half of virtual particle-anitparticle pairs from the seething mess of the quantum vacuum...

Re:GO FURTHER! by Anonymous Coward · 2000-01-15 06:51 · Score: 0

well, since the two are neighbours (sp?) in the spectrum, it is just a matter of definition.

Re:Hemos is such an idiot by Anonymous Coward · 2000-01-15 07:26 · Score: 0

Yo, pinhead: If you see a part of the story in italics it means that it's verbatim, as submitted. The error was on the part of daveb, who wrote it, and not Hemos who merely passed it on.

Personally, I'm happier that the /. staff tends not to edit submissions, but lets each writer express himself as he pleases. Please note that these writers are probably programmers, engineers or students of some kind, and therefore are amateur, not professional, writers.

While a great many /. readers are deeply interested in Linux and things Open Source, /. is not a Linux site as such. If it were, we wouldn't be seeing stories on orbiting X-ray observatories.

Re:BUT CAN IT... by Anonymous Coward · 2000-01-15 08:08 · Score: 0

You are one sick piece of shit.

You really ought to try AOL, I hear they have lots of folks just like you over there.

Expanding universe is finite for us, can be bigger by Anonymous Coward · 2000-01-15 10:59 · Score: 0

If the universe is expanding (which it is), then light traveling through an expanding universe will be "strecthed" since the space it's traveling through is expanding. It's wavelength gets longer and longer. This is why things farther and farther away look redder and redder. Their emitted light is being redshifted more and more. Obviously, there is some distance at which emitted light would be infinitely redshifted, i.e., distant points are expanding with the universe faster than the speed of light (relative to us). Since we can never receive information from beyone this barrier, no physical laws (as we perceive them) are being broken. We cannot perceive what happons beyond the sphere of infinite redshift. Thus, from out POV, the universe has a maximum volume. Gee, this sounds an awful lot like an "event horizon", yes? Perhaps the entire universe is a black hole. Assuming we know the total mass of the universe, can we not calculate what the schwartzchild radius for a black hole object of this mass is? And if we should find this radius to be just about out to as far as we can see...

Re:Hemos is such an idiot by Anonymous Coward · 2000-01-15 11:12 · Score: 0

It's "satellite", according to Webster's and American Heritage. If you're going to pick, please check the dictionary. In geekspeak: RTFM.

I didn't know the terms "slashdot", "Linux", and "professional" were synonyms; I'm reasonably sure none of the above implies mastery of English grammar and usage.

25 Kilovolts by Anonymous Coward · 2000-01-15 09:20 · Score: 0

The electrons in a CRT are generally accelerated to 25 kilovolts or so.

Re:You bit by Anonymous Coward · 2000-01-15 09:20 · Score: 0

no, I was the one who made the original post, and decided to comment on the idiot who moderated it

Re:Don't be fooled. This is all a lie. by Anonymous Coward · 2000-01-15 13:52 · Score: 0

No more alcohol for this man.

You, sir, are a typical, damned, Godless Liberal. I'll bet you'd like to enact federal laws that dictate when I can and cannot consume alcohol. I say this because that's what liberals like to do. They like to run people's lives. Well, my friend, let me tell you that I will cease my alcohol consumption when I am damn good and ready. You will not sway me, liberal. I will follow my own course, and you will either take it or leave it.

Thank you for your time.

Re:14 Billion Light Years by Anonymous Coward · 2000-01-15 13:52 · Score: 0

The most interesting thing is that these objects (theoretically "vieled galaxies") are nearly 14 billion light years away. This means (please correct me if I'm wrong) that either a) the universe is older than we thought (9-12 billon?) or b) there is matter in the universe that pre-dates the big bang.

No, all it means is that someone picked a Hubble constant such that the distance they end up with is 14 billion light years. If this was a "real" astronomical paper, they'd tell you what the redshift was and let you use your favorite value.

Re:BUT CAN IT... by Anonymous Coward · 2000-01-15 09:46 · Score: 0

send me your comments: chile_molesta@hotmail.com

What an offensive email address. Get an account with Excite or someone else... anyone but M$haft.

Re:BUT CAN IT... by Anonymous Coward · 2000-01-15 09:58 · Score: 0

What's wrong with molesting chile peppers?

Re:Getting transcendental! by Anonymous Coward · 2000-01-15 10:39 · Score: 0

Don't Panic

So, are virtual (anti)paricle pairs "the aether"? by Anonymous Coward · 2000-01-15 10:48 · Score: 0

If Hawkings is right about every point in the universe being a seething sea of virtual particles that are continually coming into existance and then annhilating one other over and over, could these paricles be the fabled "aether", once thought to be the medium that propagates electromagnetic waves? And since c is the same in all reference frames, the existance of an aether would not change the result of the Michaelson-Morley experiment that supposedly disproved the idea of an aether.

F-rays by Anonymous Coward · 2000-01-15 10:51 · Score: 0

Wow, what with xxx rays, maybe we can get these too?

Re:Is this news? by Anonymous Coward · 2000-01-15 14:05 · Score: 0

At the time, the universe was expanding much
faster than the speed of light.

Imagine I threw a baseball at you and then
someone pulled the carpet underneath you
faster than the rate of the ball. the same
applies in the universe except the light
is the baseball and the carpet is spacetime.

YOU SHUT THE FUCK UP by Anonymous Coward · 2000-01-15 14:15 · Score: 0

I've had about enough of you.

Re:How does chandra work? by Anonymous Coward · 2000-01-15 14:21 · Score: 0

Chandra doesn't work with a pinhole camera. It uses grazing incidence.

X-Rays go through almost anything at normal incidence (straight into a surface, at an angle of 0 with respect to the surface normal). And likewise at angles greater than zero. But at grazing incidence (angle near 90 degrees, skimming the surface), the reflectivity increases dramatically, following Fresnel's laws of reflection and refraction.

The mirror is parabolic, but Chandra doesn't use the nearly-spherical part near the summit of the paraboloid (like most satellite dishes), it uses a nearly-cylindrical part of the paraboloid further down the axis, where most incoming rays hit it at near-grazing incidence.

Guy Ouellette
Unemployed physicist
guy.ouellette@ri.cgocable.ca

You need help by Anonymous Coward · 2000-01-15 14:40 · Score: 0

Wow, what a burst of anger and loud shouting in public! Its been years since I've seen such a display of a mental disorder (the last time was the person in the local mall who liked to talk to himself while eating).

You seem to have an anger management problem. Perhaps this stems from your youth. Were you abused by others (parents, teachers, schoolmates) as a child? Or was it perhaps the type of problem where you were hurt personally by another person and are having trouble dealing with the issue? Such metal problems do tend to begin with outbursts similar to yours. I am worried that they usually end in violence.

May I suggest a mental health therapist? You'll find them under "Pshyciatrist" in the yellow pages. If you see do one, and get the help you obviously need, we'll all sleep better tonight.

Re:BUT CAN IT... by Anonymous Coward · 2000-01-15 06:02 · Score: 0

I STILL WANT HEMOS PICS!!!!!

if you cant provide tell me who can!! i know you have some!! share the wealth1!!

Re:Well that's very cool! by Anonymous Coward · 2000-01-15 06:16 · Score: 0

arghhhh! why are so many people here mistaking the cosmic background radiation for what chandra is observing?! they are totally different the cosmic background radiation is MICROWAVE radiation. has nothing to do with chandra!

bullshit article by Anonymous Coward · 2000-01-15 14:49 · Score: 0

From the article:
> According to the astronomers there
> may be tens of millions of these
> "veiled galactic nuclei" in the
> Universe. Each of them probably
> harbours a massive black hole at its
> core that produces X-rays as gas is
> pulled toward it at nearly the speed
> of light.

Bullshit. This is completely unsubstantiated. It should read Speculators suggest that black holes may...

Re:bullshit article by jpgrimes · 2000-01-16 06:40 · Score: 1

Actually as an astronomer this is not news much at all. There is some new science in this work but this isn't it. For over 10 years most scientists have believed that at the center of active galactic nuclei there are black holes (where else do you get the energy from). And evolution studies have hinted at this strongly for years now and MACHO studies and ...

john grimes
chandra science mission planner

Re:Is this news? by Anonymous Coward · 2000-01-15 14:52 · Score: 0

ironically the parent to my post, although useful, should be moderated -1, offtopic NOT 2!

Re:More Chandra Accomplishments by Anonymous Coward · 2000-01-15 14:55 · Score: 0

And, being a buggery child molester, you're probably also partial to Brown Holes. Go fuck yourself.

I can find out some stuff about you: by Anonymous Coward · 2000-01-15 15:04 · Score: 0

that you didn't tell us:

You live in America (In another post you told us you steal AOL accounts), in a city with a population of over 50k (you use a cable modem). This narrows it down significantly, to perhaps only 5k cities.

You use @home cable service, since you posted to the @home story. You wouldn't read and/or post to that story unless it applied to you. This leaves just a couple of thousand cities left now.

You use windows, but have tried linux, since you mentioned you prefer winamp to xmms. We are down to less than 100k people in those cities now.

You started your account on Wednesday January 12, not too long ago. Your first post seems to indicate you have lurked here for a while first.

You live with your parents and work at McDonald's. This would mean you are within 10 minutes driving distance of your destination. I bet we are down to 5k people now.

Now, with you being a 23 year old college dropout that has a computer, lives in a city with @home cable access, who works at a McDonalds, and enjoys drugs, I bet we are down to 750 suspects.

By looking at the posting times on your user account, Now it seems you work either very early at McDonald's or do a split shift. And the times seem to be concurrent with what times one would expect an east cost American to post at. Now we are down to what, 200 suspects?

I really don't have the time to figure out exactly who you are any further, but there isn't much further to go.

You are releasing too many clues, Molester.

Re:So, are (anti)paricle pairs "the aether"? no by Anonymous Coward · 2000-01-15 15:33 · Score: 0

the Michaelson-Morley experiment would still detect 'more' aether facing 'into' the oncoming 'wind of aether' (pointed along with earths revolution about the sun) than facing opposite earths revolution. EM radiation does not 'need' any medium to propagate

Re:GO FURTHER! by Anonymous Coward · 2000-01-15 06:19 · Score: 0

its not even infrared it is further down the EM spectrum at MICROWAVE frequency.

Is this news? by bugg · 2000-01-15 05:22 · Score: 0

I could have sworn I recall reading about
the entire spectrum of EM being found in space..
Gamma rays being the most popular, but hey,
X-Rays and Gamma rays arent' too different.
Is this that big of a discovery?

(1st?)

--
-bugg

Re:Is this news? by Anonymous Coward · 2000-01-15 14:05 · Score: 1

Darby, you are assuming that the cosmic background radiation came from a single point source at the origin of time (t=0). It came from an event some time after the Big Bang, when the Universe had some size. The phenomenon happened everywhere in the Universe, thus there was a large number of sources.

(I think that the other poster got confused between Kepler and Copernicus regarding the principles 1 and 2. And the models are from Friedmann, I think).

Guy Ouellette
guy.ouellette@ri.cgocable.ca
Re:Is this news? by Anonymous Coward · 2000-01-15 06:07 · Score: 1

"ramifications this has on the Big Bang theory? My guess is that it doesn't disprove it. But it sure takes a big chunk out of it..." it really dosent have any effect on big bang theory. you are mistaking the cosmic background radiation for 'background' x-radiation. the cosmic background radiation left over from the big bang is IN THE MICROWAVE BAND of the electromagnetic spectrum. chandra only detects X-rays
Re:Is this news? by Woodlark · 2000-01-15 10:56 · Score: 1

If it's radiation left over from the big bang, then didn't it radiate in all directions from the center of the universe at the time of the big bang?
If this is the case, then how come it's still here?
I mean shouldn't it exist as the surface of a sphere making up the expanding boundary" of the universe?

I hope this helps. The universe is expanding in all directions with respect to all points. What I mean is:
1- the Universe looks pretty much the same no matter where you look and,
2- the Universe looks pretty much the same no matter where you look from.
These two observations, also known as Keppler's laws, mean that there is no detectable center of expansion. The cosmic background radiation (CBR) looks like it's coming from everywhere, and somebody else somewhere else would think some of it came from us.

So, in three dimensions, the Universe has no boundary. The fact that you're imagining it as a sphere means you're confused. One of the Keppler models does imply a spherical Universe... but in 4 dimensions. Just in case you're curious, the other two Keppler models imply a saddle-shaped and a disk-shaped universe (in space time).
Droit devant soi on ne peut pas aller bien loin...

--
Droit devant soi on ne peut pas aller bien loin...
Straight ahead of him, nobody can go very far... -- Le P
Re:Is this news? by Woodlark · 2000-01-15 10:59 · Score: 1

Energy from the Big Bang has dissipated so much that infrared is the only thing left of it.

No, the universe was expanding at such a rate at the Big Bang that the light getting to us from then has been red-shifted down to the microwave zone. It is not dissipation, it is red-shifting.

Droit devant soi on ne peut pas aller bien loin...

--
Droit devant soi on ne peut pas aller bien loin...
Straight ahead of him, nobody can go very far... -- Le P
Re:Is this news? by Darby · 2000-01-15 10:23 · Score: 1

True,
But maybe you can clear up something that bugs me about the whole "background radiation" thing.
If it's radiation left over from the big bang, then
didn't it radiate in all directions from the center of the universe at the time of the big bang?
If this is the case, then how come it's still here?
I mean shouldn't it exist as the surface of a sphere making up the expanding "boundary" of the universe?
This question never occurred to me when I was in physics class but it seems to make sense.
Where is the flaw?
---CONFLICT!!---
Re:Is this news? by Gurlia · 2000-01-15 06:08 · Score: 1

No, the EM radiation is infrared, not X-ray. Energy from the Big Bang has dissipated so much that infrared is the only thing left of it. Any radiation with higher frequency (eg. X-rays here) must certainly come from objects like stars, quasars, black holes, and the like. This does not affect the Big Bang theory at all.

--
mikre he sophia he tou Mikrosophou.
Re:Is this news? by GMOL · 2000-01-15 07:03 · Score: 1

Maybe I don't understand something about /. moderation, but the above poster is absolutely correct, the people talking about the result taking a chunk out of big bang theory are making a catagoreical error; certainly doesn't deserve a score of 0. Why the hell do some people just HAVE to comment on something regardless of the fact that they know they don't know what they are talking about?
Re:Is this news? by Alex+Belits · 2000-01-15 08:40 · Score: 2

Maybe I don't understand something about /. moderation, but the above poster is absolutely correct, the people talking about the result taking a chunk out of big bang theory are making a catagoreical error; certainly doesn't deserve a score of 0. Why the hell do some people just HAVE to comment on something regardless of the fact that they know they don't know what they are talking about?

The article wasn't moderated -- all anonymous articles start with the score 0, as opposed to normal users. Moderators later can moderate anonymous articles up, but this one was just posted, so it remained with its initial score.

--
Contrary to the popular belief, there indeed is no God.
Re:Is this news? by edhall · 2000-01-15 10:05 · Score: 2

I think the issue here is that a post based on misinformation has been moderated upward twice as "Informative" while a post providing correct information languishes at zero. The facts here shouldn't be controversial: even if the Big Bang Theory is a Big Bust, or even if the cosmic background radiation is a measurement error (doubtful, but for the sake of argument let's say it is), such radiation is in the microwave region, not X-ray. So this new discovery has nothing to do with the background radiation claims of the Big Bang Theory.

I don't want to be hard on the original poster-- many is the time that I've had this kind of an "Aha!," then further information shows me to be embarrassingly mistaken. And I'm sure the two moderators made exactly the same mistake the poster did. This happens all the time on Slashdot where something seems insightful/interesting/informative at first glance and gets moderated up (moderators are busy people, after all), with a correcting post coming some time later when there is so much else competing for moderators' attention that the correction lays untouched at 0 or 1.

Even though this offends my sense of justice a bit--misinformation getting marked as "informative" isn't one of moderation's finest hours--moderation works well enough that cases like this only call for its imporvement, not its abolition.

As for whether the original article being "news:" Hell, yes! The cosmos proves more wondrously strange each time we expand the "eyes" and "ears" we use to examine it. There is a good chance that there will be far more questions than answers generated in astrophysics during our lifetimes, given the new technologies we'll be able to point "out there," but that makes it all the more interesting and inspiring.

-Ed
Re:Is this news? by Weezul · 2000-01-15 08:34 · Score: 2

I'm not an astronomer; anyone know what the ramifications this has on the Big Bang theory? My guess is that it doesn't disprove it. But it sure takes a big chunk out of it...

I doubt it has much influence on the big bang theory, but it is worth mentioning that there are a few reputable scientists which have doubts about the big bang.

The conspiracy theorists love to point out how the Vatican commishioned a priest who knew some physics to reinvolve the church in the discussions of the origin of the universe, then this guy descided that the idea that pushing something like the big bang on the scientific community would be the best way to do that. This guy ran arround to various scientists tring to push the idea and got noware untill people noticed the universe was expanding, then people started beliving him. (Note: You should not take this story as an argument against the big bang, but as a warning about how religious people follow there biases)

It is a good test of your understanding of the scientific method to think about exactly why the expansion of the universe provides evidence for the big bang. Example: if we lived in a cluster of galixies which had an eliptical orbit arround soemthing really big then it might appear that al the galaxies were moving appart. It's fun to think about what exactly is wrong with this alternative explination.

Jeff

--
The Christian religion has been and still is the principal enemy of moral progress in the world. -- Bertrand Russell
Re:Is this news? by Magic+Snail · 2000-01-15 05:32 · Score: 3

Actually, it is. All electromagnetic radiation is easily pinpointable to a certain star, or cluster, or galaxy. But there was always a universal background radiation. Before now, everyone thought that the cosmic background radiation was heat (and EM radiation) left over from the big bang, still in the process of dissipation.

I'm not an astronomer; anyone know what the ramifications this has on the Big Bang theory? My guess is that it doesn't disprove it. But it sure takes a big chunk out of it...

Ryan Kirk
rkirk@calpoly.edu
http://topflight.net

This should be front page news!! by Galilee · 2000-01-15 11:47 · Score: 0

This project is a success, at least so far, and the story was buried in the newspaper. If the project crashed and burned the reporters would be screaming about NASA's latest failure. each and ever one of us would now how much money was "wasted" on the project.

This is what bothers me the most about coverage of the space program. Most people can't name 3 people that where on the latest shuttle mision, but they can name the last 3 failures.

Re:This should be front page news!! by Galilee · 2000-01-15 13:09 · Score: 1

please ignore the repeatative postings. i have to stop posting alte at night.

This should be front page news!! by Galilee · 2000-01-15 11:48 · Score: 0

This project is a success, at least so far, and the story was buried in the newspaper. If the project crashed and burned the reporters would be screaming about NASA's latest failure. Each and every one of us would now how much money was "wasted" on the project.

This is what bothers me the most about coverage of the space program. Most people can't name 3 people that where on the latest shuttle mision, but they can name the last 3 failures.

Satellite has two L's in it by Anonymous Coward · 2000-01-15 07:48 · Score: 1

I think errors like this make it look so unprofessional.

Welcome to the club, baby, yeah!

Re:This is big by Anonymous Coward · 2000-01-15 07:50 · Score: 1

Dark Matter arises out of the fact all parts of a galaxy revolve around the system at nearly the same speed.. Which according to the laws of orbital mechanics Kepler and Newtown devised that isn't possible. So Dark Matter isn't anywhere deep in the universe it is right here with us in our own galaxies. Also, in terms of making the universe a closed system, it might be a little premature for that, however if there is other galaxies out there and alot of them, that might explain some measurements of universal expansion which suggest the universe is flying apart faster.

Don't be fooled. This is all a lie. by Anonymous Coward · 2000-01-15 11:32 · Score: 1

As I watch the liberals here on Slashdot slobber all over these so-called "results", I cannot help but be saddened at the state that our society has sunk to. Reality check, friends: There is no Chandra X-Ray Observatory, and therefore there are no results from it. What you're looking at are a bunch of complete and total fabrications, lovingly assembled in Adobe Photoshop. The thing about modern technology is that it makes it much easier for NASA to fake its results. When they faked the landing on the moon, NASA had a difficult chore. They had to show live-action people on the surface of the moon, using completely practical effects and sets, since digital technology wasn't invented yet. They had to construct elaborate sets -- financed by your tax dollars, friends -- on which to work. Of course, being liberals, the perpetrators of this cruel prank didn't have any trouble getting the money. They just raised our taxes.

But now, NASA has it easy. By using digital technology and image processing software, they can generate anything that they want. They can scan a maple leaf or a half-eaten bagel, import it into Photoshop, invert it, switch the palette, and claim that it's a "black hole at the center of the galaxy M87 Virgo A." Hogwash, friends. Hogwash. God is not fooled, and neither am I. There are no black holes. There are no other "galaxies". The same can be said for all other types of deep-space objects. "Quasi-stellar radio sources?" What blatant liberal jargon! These are distractions, friends, distractions. Which brings me to my next point.

The astute reader is now wondering where all of our taxpayer money has gone, if in fact there is no Chandra X-Ray Observatory. The answer, I am sorry to say, is quite disturbing. NASA is nothing more than a front, a pseudo-agency established by liberals in the middle part of the previous century. The liberals wanted to put together something that sounded really expensive. And what sounds more expensive than space travel? What better way to fool millions of people and cheat them out of trillions of their hard-earned dollars?

And so began the Liberal Funding Agency. The money allocated by Congress to NASA is immediately funneled into various left-wing organizations. A sizeable chunk is used to prop up Communist dictators around the world. A large portion goes to fund Planned Parenthood clinics in cities around the nation. The National Organization for Women gets a piece of the action too. Same thing for various homosexual and black groups. The liberals also use this money to attack our children. They buy certain unacceptable books to stock public libraries with. "On the Origin of Species" by Darwin and "A Brief History of Time" by Hawking are among these heretical books. Their top priority is to enslave children; always has been, always will be. And our money is helping them do it.

So what you need to do, friends, is write your congressman and demand that NASA be dissolved immediately. Strike a blow against liberalism and multiculturalism. If we can work together, we can bring these people down once and for all. Thank you for your time.

Re:Don't be fooled. This is all a lie. by jpgrimes · 2000-01-16 06:12 · Score: 1

Man, I'm really wasting my time now. Spend all my time plannong Chandra observations for a telescope that doesn't exist. Somebody must be having a lot of fun when things get nuts and I get calls at weird times of day. Maybe I should find a new job.
john grimes, Chandra Science Mission Planner
Re:Don't be fooled. This is all a lie. by Medieval · 2000-01-15 13:42 · Score: 1

No more alcohol for this man.
Re:Don't be fooled. This is all a lie. by Wubby · 2000-01-15 23:45 · Score: 1

Wow, You mean I'm getting paid decent money
to maintain the networks for a Control Center that
doesn't do ANYTHING. You mean I watched a FAKE
satilite drift from a FAKE shuttle as it was
supposed to be happening?
Thanks, you opened my eyes!

--
Sig
Appended to the end of comments you post. 120 chars

Re:How does chandra work? by Anonymous Coward · 2000-01-15 14:20 · Score: 1

Chandra uses a set of barrel-shaped mirrors (one set is a paraboloid section, and the second set is a hyperboloid section) to focus incoming x-rays onto science instruments at the back of the telescope. The mirrors and their focal length have been designed ("tuned") to focus certain wavelengths of x-rays.

This link might give you some of the info. that you are looking for:

http://xrtpub.harvard.edu/about/hardware.html

A new European Space Agency x-ray telescope has more mirror surface area, but does not have the resolution of Chandra. They are complementary spacecraft.

A black hole do not grow faster than other objects by tamyrlin · 2000-01-15 11:25 · Score: 1

Well, if something falls into the event horizon the hole will grow.

But so will anything else if something hits them. The earth for example is constantly bombarded with particles from space.

Consider a star with the mass m and radius r.
Then consider a black hole with the same mass.

At the distance r from the center of that black
hole you would feel exactly the same gravitational pull from the black hole as you would feel from the star if you were standing on its surface.

The difference is that the gravitational pull of the black hole keeps increasing if your distance is less than r. This is in contrast to the gravitational pull of the star if you are inside it. (Since you have lots of mass around you pulling at you you can no longer simplify the star as a point formed gravitational source.)

So, you would actually have a harder time getting a black hole to grow as opposed to getting a star to grow since objects can pass closer to the black hole without crashing into them.

(Allright, some inaccuracies in this post, a star does not have a surface you can stand on, and it also loses mass by emitting energy, etc, but that isn't the point of the post)

Re:about dark matter by shogun · 2000-01-15 18:03 · Score: 1

but if matter tended to group together that much you'd expect larger stars to be more common than smaller stars.

Well that may be the case, however the bigger a star is the faster and hotter it burns its nuclear fuel and hence the shorter its life. Therefore there may actually have be more high mass stars in total over time, but at any one time there is going to be more of the stable long lived low mass stars.

Re:X-rays can beat black hole gravity? by Luyseyal · 2000-01-15 05:28 · Score: 1

the X-rays are released from the accretion disk around a black hole as the matter accelerates into the hole before the matter reaches the point of no return.

-l

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Re:about dark matter by Woodlark · 2000-01-15 11:08 · Score: 1

a lot of people like to believe that black holes are common, but if matter tended to group together that much you'd expect larger stars to be more common than smaller stars.

Hmm... I just read an article in yesterday's paper about Chandra discovering a whole new swath of black holes. Here's the Yahoo bit. They're all under News Stories and notice how they're all in the last three days. Yahoo links.

That's really neat that this /. article is about September news from Chandra when Chandra just made news again this week.

Droit devant soi on ne peut pas aller bien loin...

--
Droit devant soi on ne peut pas aller bien loin...
Straight ahead of him, nobody can go very far... -- Le P

Re:14 Billion Light Years by Woodlark · 2000-01-15 11:17 · Score: 1

In fact, the influence of surrounding matter would certainly be a good explanation for why the known universe is "lumpy".

Erm, I don't know about you, but I find Heisenberg's Uncertainty Principle a much better explanation for why the known universe is lumpy. If it had been totally smooth while in the singularity, we'd have known the positions and velocities of everything! As it is, there were irregularities in the singularity which are also expressed as lumpiness now.

Another theory for why the Universe is lumpy is that there could be different parts of the Universe, some lumpy, some smooth, some curly, some I don't know what. But lumpy is what we needed to get where we are, so the Universe is lumpy so we can observe that it's lumpy.

Ahh, circular reasoning at its best.

Droit devant soi on ne peut pas aller bien loin...

--
Droit devant soi on ne peut pas aller bien loin...
Straight ahead of him, nobody can go very far... -- Le P

Re:14 Billion Light Years by Ken+Broadfoot · 2000-01-15 09:18 · Score: 1

You seem to know this stuff! This point:

"We can observe that two regions of space which are not causally connected (ie a light signal cannot have travelled from one object to the other within the age of the universe) abide by the same laws of physics without there being any real reason why they should."

The fact that there CAN be two regions of space that are not causally connected lends support to "Inflation" correct?

I have always had a problem grasping that conjecture in the Big Bang theory. It is like we get to suspend the light speed limit for a few time factors of 10 just to make observations fit better.

If you have any more insight to this phenomena I would like to hear it.

--
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Re:about dark matter by Witchblade · 2000-01-15 16:56 · Score: 1

MACHOs are interesting in their own right, but have almost nothing to do with dark matter. Overwhelming evidence shows that dark matter is around 90% of the mass of the universe, and it must be nonbaryonic. For the non-physicists out there, this means it cannot be made of protons, electrons, and neutrons. Everything that emits or reflects light (including planets, small stars, and the matter contained in black holes) is baryonic. Hence the designation of "dark" for the other stuff.

Re:This is big by Axe · 2000-01-16 03:56 · Score: 1

Can these non visible galaxies be counted?

Dark matter is a bit more local observation - by looking at the rotation speed and mass distribution of OUR OWN galaxy, we can conclude that most of its mass is not visible as stars. So it is not directly related to observing far away galaxies. - But it affects our estimate of the average density of matter in the universe.

These new galaxies were not visible because x-rays dissipate less over distance. New gamma ray observatory (GLAST) will see even more distant objects.

--
<^>_<(ô ô)>_<^>

Re:about dark matter by Axe · 2000-01-16 04:11 · Score: 1

There is nothing wrong with "chalking it up" to the dark matter. Accepting possibility of MACHO of minimal sypersymmetric neutralinos (I have done simulation on possibilities to detect them, for my thesis - it looks like we will have to wait a bit :) - have less impact on current theories than questioning gravity. And the rule of thumb is - first think about a less radical proposition: question foundations of the theory only when nothing else works. It may sound not very "imaginative" but it is the best approach found so far. This research is hard enough without having to rethink all the basis every week.

--
<^>_<(ô ô)>_<^>

Re:about dark matter by Axe · 2000-01-16 04:14 · Score: 1

I meant MACHOS or neutralinos of course. Theses are very different ideas...

--
<^>_<(ô ô)>_<^>

Dang.. by Axe · 2000-01-16 04:16 · Score: 1

...I lost my ability to type and read. And you say question gravity. I will die here then.. Let it be Dark Matter...

--
<^>_<(ô ô)>_<^>

Re:That's Hawkings radiation by Axe · 2000-01-16 04:21 · Score: 1

due matter falling into the accretion disk

Err, not to be picky or something - it IS the accretion disk.. Very hot plasma around the black hole (but Above horison of course - in fact the closest part of the disk is (should be) about three times the radius of the horizon - depending on the rotation of the black hole)

One number that is very surprising - the matter falling into black hole can convert almost half of its rest mass into energy to radiate! Much more effective than fusion can be.

--
<^>_<(ô ô)>_<^>

Re:So, are virtual (anti)paricle pairs "the aether by Axe · 2000-01-16 04:25 · Score: 1

If Hawkings is right about every point in the universe being a seething sea of virtual particles

With all due respect to Dr.Hawking - it is far from being his idea.

From what I remember from "Physics of vacuum" course I took 8 years ago, there is a rather fancy way to avoid violating relativity dealing with this "sea" of particle. Until MathML is standartised, I can not quote relevant fromulas here :) (well I can not quote them because I slept thru most of the lectures... anyway)

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<^>_<(ô ô)>_<^>

Re:3 Questions by baglunch · 2000-01-16 01:58 · Score: 1

1.) Couldn't we consider the location of the big bang singularity to be "the centre of the Universe"? I don't know relativity at all, so this may be a counter-intuitive feature of relativity, but even if EVERYTHING is expanding, then things on the OTHER SIDE of the point of the singularity would appear to be expanding away from us faster than the things that are expanding away from us nearby, right?

2.) Once a wavelength gets altered in its journey, how can you tell that it was ever a different wavelength?

3.) My own amateur and thoroughly unresearched thought on the age of the universe is that the universe is spacially infinite (and not in a mobius strip sense). There may have been a big bang that caused our own neck of the woods, but I think that you could fly right out of our "universe" and into the next one without even realizing it (except that everything would suddenly be moving apart at a different speed than we are accustomed to). My logic behind this is:

a.) If you accept that the light we are seeing from distant galaxies is x years old with a direct correlation to the speed of light in a vacuum, then it makes sense that if we just look past those galaxies we'll see farther and farther into the past, right? And somewhere farther in the past is the Big Bang. Have we just not built a powerful enough telescope to see the Big Bang yet? Even if you agree with some arguments saying that the universe expanded much faster than the speed of light, the light given off from it would tend to travel... at about the speed of light, right? So we may never see the light on the leading edge of the BB, but we'd HAVE to see the light from the trailing edge at some time... if the Big Bang expanded at more than three times the speed of light, then perhaps the light from the trailing edge is still traveling at twice the speed of light away from us?!? Light traveling faster than the speed of light has to throw a wrench into someone's equation.

Again, thanks.

--

Work is for people who lack the imagination to play.

Re:Getting transcendental! by baglunch · 2000-01-15 13:54 · Score: 1

Name a microbe (bacteria/virus) that can kill a person. I don't know of one. It takes countless millions of them replicating and replicating to kill anything. Humans aren't necessarily so different...

--

Work is for people who lack the imagination to play.

3 Questions by baglunch · 2000-01-15 14:38 · Score: 1

1.) If there were a Big Bang that everything exploded from, why are we not substantially closer to one side of the background than the other? Say we look in a direction and the background is 14 billion light years away. We should be able to turn around in the other direction and see the background at 5 or 60 billion light years away, right? I didn't plug any math into this, I'm not making a point, just asking a question.

2.) X-rays are just another wavelength on the electromagnetic spectrum, right? What says that a wavelength can't get changed in the course of its travels across the universe? Passing through nebulae, slipping around black holes, etc. seems like a wavelength would change fairly often from light year to light year, right? What makes us so sure that the x-rays CHANDRA is imaging are pristine, untampered, reliable wavelengths? Is there no method of turning a microwave into an x-ray, and vice versa, or even degrading the wavelength into the visible spectrum (and back)?

3.) If we really are seeing 14 billion years into the past, and this represents something close to the beginning of the universe, why are we seeing galaxies? The big bang isn't reported to have exploded into tidy little galaxies. Why aren't we seeing large, hazy globs or strings, or something? If we are seeing galaxies (or whatever being viewable as bounded pinpoints), then doesn't that imply that the universe is vastly older than the oldest images we have yet seen?

Thanks.

--

Work is for people who lack the imagination to play.

Re:3 Questions by jpgrimes · 2000-01-16 06:25 · Score: 1

Sign,
1) The universe is expanding.
Think about a pool of water. your thinking that if I cause a circular wave to start in the pool we have a center of that wave. But thats not what is happening. More equivalently would be that the whole pool grew. And to make in even more equivalent the pool which I am comparing to a universe is not in ground.
So at the beginning there was one point. Now that one point has grown to all points, so all points are that center point, as there is no center.
Does this help?

2) in a way you can't tell directly it was at a different wavelength. What you generally do is take a spectra of an object (lets say galaxy). The spectra tells me how many photons it is emitting at a certain wavelength. Now we know that most matter is hydrogen (can tell from the local universe) and we know the atomic transitions of hydrogen and at what wavelengths (on Earth) hydrogen gives off a lot of light. So basically we will compare the local galaxy (and our knowledge of atomic physics) to that far off galaxy and compare the shifts in wavelength. This is very, very reliable. Good question.

3) I don't want to touch this. Not because its all wrong, but because its my poor explanations skills will only confuse you more. Read more

John Grimes
Chandra Science Mission Planner

Near IR, Far IR, Submillimetre, Microwave by Christopher+Thomas · 2000-01-15 13:30 · Score: 1

well, since the two are neighbours (sp?) in the spectrum, it is just a matter of definition.

Leaving aside the fact that there is a _huge_ distance between an average-frequency IR photon and an average-frequency microwave photon, there is another band in between the two, called "submillimetre" in the references I use.

The reason the article's observations on x-rays are important is that, while we knew that there were substantial quantities of x-rays being emitted from most directions in the universe, we didn't know where they were being emitted from (just that it was roughly uniform). The telescope had a much higher angular resolution than anything else we can look at the x-ray background with; it discovered that most of the x-rays were being emitted from tight regions in the same place as galaxies that we've seen using other telescopes. Thus, most of the x-rays are probably coming from galactic cores.

Re:Daily Astronomer by Foddrick · 2000-01-15 15:46 · Score: 1

This is an excellent site.

We really need a SlashBox(tm) for this one.

Re:How does chandra work? by jpgrimes · 2000-01-16 06:30 · Score: 1

try chandra.harvard.edu
specifically http://chandra.harvard.edu/about/telescope_system. html

john grimes
chandra science mission planner

Re:How did they calculated... by jpgrimes · 2000-01-16 06:36 · Score: 1

This to first order is correct, but think back to freshman physics (this is a simplification)

distance=time*velocity+.5*time^2*acceleration

Now this equation is very wrong in that its newtonian mechanics not GR but the GR equation is no where near as simple. But Hubble's comstant is basically your velocity term and then we have an accleration term (that recent evidence suggests is not sero) and then ...

Its a complicated equation that depends of constants that we only have very rough guesses for.
john grimes
chandra science mission planner

Re:Or turn it around... by auntfloyd · 2000-01-15 09:29 · Score: 1

Of course, you're making the (somewhat presumptuous) assumption that there are no other intelligent beings in the universe. While I am no UFO fanatic, I think it is *way* too early to make such a statement.

~~~~~~~~~
auntfloyd

Re:14 Billion Light Years by auntfloyd · 2000-01-15 06:15 · Score: 1

But the aliens?
The space-worthy DC-10s (which are modern aircraft)?
The evil overlord Xenu?
The $100,000 'treatments'?

You're not going to tell me that a 'religion' founded by a hack sci-fi writer based on spaceships and alien psychologists is fake, are you?

Geez, not even L. Ron's *cult* is imaginative. No wonder he was such a failure.

~~~~~~~~~
auntfloyd

Re:What noone has said - Congratulations! by B.D.Mills · 2000-01-16 06:21 · Score: 1

You're right. Considering how hard it is to focus X-rays, it is an amazing achievement.

To focus X-rays, one can either find a material that refracts X-rays so that lenses can be built, a material that reflects X-rays so that a reflecting telescope can be built, or find an alternative focusing technique.

X-ray lenses can be built, but the mass of metal required to bend X-rays to a respectable focal length may be too great for a satellite. X-ray mirrors may not be possible. I don't know what they actually use in the satellite, but I think they use an array of mirrors that reflect X-rays in a glancing manner, such that the incoming X-rays are almost parallel to the mirror.

It is interesting to note that the compound eyes of insects focus light in the same manner. Therefore, if the engineers wanted to make another X-ray telescope, they should consult entomologists and study the structures in insect eyes so that the next generation of X-ray telescopes may copy the design principles of insect eyes.

--

The only thing necessary for the triumph of evil is for good men to do nothing. - Edmund Burke

Re:about dark matter - it's simple by mudshark · 2000-01-16 10:02 · Score: 1

The presence of dark matter can be explained in very simple terms, and can be demonstrated on an everyday basis: it is the observation of stupidity in its physical manifestation. Sort of like "potential stupidity" as opposed to the "kinetic stupidity" that we see around us.

Some scientists say that the major building block of the universe is hydrogen because it's the most plentiful element, but my theory is that the universe is made out of stupidity, because it is more plentiful than hydrogen.
-- Frank Zappa

--
In other news, astrophysicists have announced that they now know what all that dark matter is: it's stupidity.

Re:Hemos is such an idiot by Primer · 2000-01-15 07:28 · Score: 1

And yes, I'm an idiot too! I should have proofed my text one more time before submitting. Thing is, I'm not running a popular site, that should live up to a certain standard. I'm just a guy who comments.

--
This is necessary...life, feeds on life...

You bit by Tony-A · 2000-01-15 08:08 · Score: 1

'nuff said.

Re:X-rays can beat black hole gravity? by jtdubs · 2000-01-15 06:23 · Score: 1

Obviosly, matter can not be created nor destroyed. However it is theorized that particle, anti-particle pairs are winking into existance all over place and then they collide into eachother and cancel back out again. When a pair is created near the boundary of a black hole it is possible that one of the pair will be sucked in while the other is not. This lone pair then escapes and appears to us to be radiation coming out of the black hole. Atleast, as far as I know... :-)

Re:Black Holes by Kesh · 2000-01-15 06:42 · Score: 1

Black holes do grow in a sense, but it's terribly gradual. As they accumulate matter, they become more dense. More dense means a higher gravitational pull, which means a larger area is affected by it. So, the object itself may not grow much, but its event horizon can slowly expand over time. Still, you're more likely to have a rogue hole drift into the solar system and hit something than have one expand enough to affect us in any amount of time that matters.

How did they calculated... by anatoli · 2000-01-15 19:08 · Score: 1

the distance(s)? I thought that in order to do that, one identifies known emission lines, finds the redshift, multiplies by Hubble constant, and gets the distance. Since many of the x-ray sources do not emit visible light, what is the procedure in this case? I mean, how do they even know that these are x-ray sources and not say redshifted gamma-ray sources?

Moderate this down (-1, Dot Your "r"s, Cross Your "h"s)
--

--
Industrial space for lease in Flatlandia.

Re:Dark matter as "optical molasses"? by moller · 2000-01-15 08:48 · Score: 1

If the dark matter is as dense as many calculations suppose it to be, it would have a strong enough gravitational field to bend the light that went by it. So even if it were "transparent" there would still be distortion because the dark matter is so dense.

Actually, that's one of the methods for detecting dark matter and/or black holes. Astronomers lookd for instances of gravitational "lensing," where a very massive object has distorted the light from a distant star. By measuring the distortion we can get an idea of the mass of the object causing the lensing.

Re:Too big to evaporate by moller · 2000-01-15 08:55 · Score: 1

;) Way too big to evaporate. Most black holes have > 3 solar masses, and it would take over 100 billion years for those to evaporate from giving off Hawking Radiation. Oh, and they do evaporate with a huge explosion, but since it's going to take so damn long we really don't need to worry about it.

Or turn it around... by Tim+Behrendsen · 2000-01-15 09:05 · Score: 1

Now comes the bottom line: how insignificant am I, a human, in a cosmic scale? ...

Let's say that intelligence is truly unique in the Universe, and we are the only examples. That means even the lowliest human being is unique on a cosmic scale. After all, after you've seen the couple dozen or so star types, you've seen them all. But there's only one place in the Universe you'll find intelligence.

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I think the BH may actually decrease in size by chainsaw1 · 2000-01-17 07:26 · Score: 1

I read somewhere that a far tangeable result of quantum mechanics, Einsteineian theories, etc. that Black holes must actually evaporate. This obviously is very contrary to what you would expect, and the rate of evaporation reflects that (something like 1^-100 gram/yr).

I don't know if this includes everything that gets sucked into the black hole, but it may very well since classic physics gets unclassical as matter accelerates to near c (speed of light).

For instance, using LaGrange equasions as v->c, the length/size of an object approaches infinity, time change approaches 0, etc. with respect to a stationary observer. This means a blach hole has infinite timeless mass? While I doubt that, there are other cleve ways of explaining what could happen.

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- Sig

Re:Getting transcendental! by Galilee · 2000-01-15 11:43 · Score: 1

In contrast to the size of the universe, people are even smaller than microbes, and therefore of less importance. Afterall, one microbe (bacteria/virus) can infect and kill a person. I doubt that on person could do the same to the entire universe.
Regardless, it is stuff that I like to think about which makes my head spin!

This should be front page news!! by Galilee · 2000-01-15 11:50 · Score: 1

This project is a success, at least so far, and the story was buried in the newspaper. If the project crashed and burned the reporters would be screaming about NASA's latest failure. Each and every one of us would know exactly how much money was "wasted" on the project.

This is what bothers me the most about coverage of the space program. Most people can't name 3 astronauts that where on the latest shuttle mision, but they can name the last 3 failures. I think it is because it is easier to understand, and report, a satelite crashing into a planet than it is to understand a discovery such as this.

Re:More Chandra Accomplishments by Crixus · 2000-01-15 10:03 · Score: 1

Here's a link to another story about another one of Chandra's accomplishments: finding "the coolest black hole ever detected".

If you ask me, ALL Black Holes are cool. ;-)

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Ignore Alien Orders

There's a good website about this on... by RonaldReagan · 2000-01-15 12:41 · Score: 1

http://www.tgwbp.addr.com/cgi-bin/wwwboard.cgi

X-rays can beat black hole gravity? by Hello+folks · 2000-01-15 05:25 · Score: 1

>>X-rays come from hot gas, usually heated to millions of degrees by falling into a black hole or scattered into space by a stellar explosion. They do not penetrate the Earth's atmosphere so satellites must be used to detect them.

Even light gets sucked in by black holes, yet X-rays can get out? Does anyone know anything about this? I'm somewhat skeptical, but since i know nothing about the subject, any knowlege would be appreciated.

Re:X-rays can beat black hole gravity? by SEWilco · 2000-01-15 05:49 · Score: 3

Here's a drawing. As stuff gets sucked in, it swirls around. Very fast. As it speeds up and the particles bump into each other they heat up. They heat up as much as they can heat up. As they fall screaming in, some of the "heat" leaks away as photons in the X-Ray spectrum.
Re:X-rays can beat black hole gravity? by Constellation · 2000-01-15 05:38 · Score: 4

Actually the X-rays don't escape the black hole. the current theory is (since we have never actually "seen" a black hole) is that as particles fall in to the balck hole, they enter a sort of, spiraling, decaying orbit (called the accretion disk). It is the friction between all of these particles in the accretion disk, that generates the x-rays. If the x-ray is released in the right direction it can escape being sucked into the black hole, since the accretion disk exists outside of the black holes event horizon.

Re:More Chandra Accomplishments by JustShootMe · 2000-01-15 13:41 · Score: 1

Being an undersexed geek, I would have to agree, and state that most pink holes are cool too. :)