Hubble vs. Webb - How Far Back Will They See? 315
Roland Piquepaille writes "According to Forbes, reporting in "Peering Back At The Universe's Past," space telescopes are really acting as time machines. They can watch objects which are so far from us that light has taken billions of years before reaching their mirrors. The Hubble telescope is able to look at events that took place 13.3 billion light-years ago. But the James E. Webb space telescope, currently under construction, and scheduled to be launched in 2011, will be able to see even further and catch phenomena which happened 13.5 billion light-years ago. The astronomers think the Webb telescope might even be able to see up to 13.7 billion light-years ago, when our universe was just 200 or 300 million years old. We are used to see fantastic images from Hubble, without paying too much attention to the characteristics of the telescope itself. So here is a thorough comparison between the two space telescopes."
Light-Years!=Time (Score:4, Insightful)
It is more accurate to say that the hubble could see images 13.3 billion years ago, and the Webb telescope may be able to see images 13.7 billion years ago.
Re:Light-Years!=Time (Score:5, Funny)
I know a man from Kessel who thinks differently...
Re:Light-Years!=Time (Score:2)
Now that sounds even stranger. The telescope wasn't even built back then... Put the word "from" in the appropriate place to make it better, or start talking about distance and how far away the objects are instead.
Lighten up! ;) (Score:2)
If they could start changing the little things [gsa.gov], they can use light-year as a time measure for another year for all that I care
Re:Light-Years!=Time (Score:2)
Re:Light-Years!=Time (Score:2, Interesting)
Re:Light-Years!=Time (Score:5, Informative)
Well, in a Newtonian sense, yes...
Einstein will tell you that time = distance. You just have to use the proper conversion factor (c, the speed of light in a vacuum) to get your units right. In relativity work, we often use units where c = 1. Time and space then behave identically in the math and you don't have to do one thing for one dimension and something a little different for the other three.
c, by the way, is exactly 299,792,458 m/s. EXACTLY. The meter is _defined_ as the distance a photon travels in exactly one second. (The second has a much more complicated definition)
So yes, light-years measure distance. And they measure time.
Quick! (Score:5, Funny)
Then we can look into the history of our own Earth!
Re:Quick! (Score:5, Funny)
Re:Quick! (Score:3, Interesting)
Re:Quick! (Score:3, Interesting)
Unless I flubbed up the calculations somewhere, which is possible, you'd need a telescope with a diameter of 480 million kilometers. Or you'd need two gig
Re:Quick! (Score:2)
What, they'll come down and admit they did it? ;-)
Statistically speaking, it's more likely that they already know because they were there and saw it in real-time. Or that we could do like in The Light of Other Days [tor.com] (a good read, I recommend it) and peek back in time through quantum tunneling effects. Call Wesley [wilwheaton.net], he'll know exactly what to do.
Using faster than light travel... (Score:3, Informative)
... to drop a camera X light years from us is a horrible kludge. FTL violates causality by definition, therefore it is physically equivalent to time travel [google.com]. You may as well just go back in time directly and observe our past at arbitrary closeness.
Re:Using faster than light travel... (Score:3, Informative)
As for hyperspace -- ill-defined term, interchangeable with "carried by angels" or "magic beans". You may as well just ask the genie in the witch's mirror to show you the past.
Do not meddle in the affairs of scientists, for they are grumpy and quick to anger (especially before their coffee).
Re:Quick! (Score:5, Interesting)
Say someday we managed to put out a large mirror...say... X number of lightyears from Earth, where X was half the number of years you wanted to be able to look into Earth's history. Here's what I'm curious about:
1.) Assuming you could get the mirror out there and set up at light speed, it would make sense that the first image of the Earth we would get back was of the craft toting the mirror leaving Earth...well, actually, probably not, since it would logically take some pre-lightspeed travel first. But you get my drift.
2.) Assuming FTL travel, could you actually see into a point in time before the point the mirror left Earth?
3.) What size mirror would be needed for a telescope to be able to capture a reflected image? Would it even be possible? Perhaps with refraction from other celestial bodies (like they've done to enhance Hubble's distance viewing).
Re:Quick! (Score:2)
If you travel faster than the speed of light, do we get a massive flash of light? Screw fireworks, soon we'll be having the military fly planes over on the 4th of July.
Re:Quick! (Score:2, Informative)
Actually, you do. It's called Cherenkov radiation, and it's very similar to the way a sonic boom forms, with waves piling up. It's a kind of eerie blue light, I believe.
Re:Quick! (Score:4, Informative)
On point 3) though, you'll have a big problem. The diffraction limit of an apertures defines the smallest angular detail you can see, and for any appreciable distance from the earth, you rapidly lose any interesting information. You also have the problem that planets which are illuminated by their parent stars, which are up to ten billion times brighter than the light reflected from the planet's surface towards you.
This is what the Terrestrial Planet Finder mission is trying to do - it is trying to see the light of other earth-like planets around other stars, and the diffraction effect for finite sized mirrors means that the light of a planet is buried within the diffraction halo from the parent star, by a few million times. Two proposed techniques to improve detection of planet light include nulling interferometry, and coronagraph optics.
Interferometry takes the light from two widely separated telescopes and combines them such that the parent star light is nulled out whilst the planet light passes through (essentially a fantastically accurate spatial filter) and the coronagraph has a black disk flying in front of the telescope blocking the light from the central star.
Dr Fish
Re:Quick! (Score:5, Informative)
The solution is to look for mirrors that are already in place (or put a large number of mirrors in place for future generations). This sounds absurd, but remember this: black holes can theoretically wrap light around at exactly 180 degrees at a given point from their centre. So we already have a number of mirrors out there. Now the big problem: black holes will have huge distorions around them, and very little light reaching them in the first place, so it's doubtful that you would be able to see anything remotely useful. This is also the problem with placing artificial mirrors: the light returned would be so small, that it would be useless. So much for looking back in time.
Distance Units? (Score:5, Insightful)
Re:Distance Units? (Score:2, Insightful)
At least this is what I understand, I am not an Astronomer or Physicist.
Re:Distance Units? (Score:2)
if one can see an object N light years far, then the particle of light meeting the eye (observer) travelled that N light years and the event being witnessed is of the time when the particle of light started travelling. Hence, light years far is light years ago - looking back in time.
It's spacetime, man (Score:3, Informative)
A light year is a valid distance measurement since the speed of light is a constant. It's as valid as defining the distance between home and work as "10 minutes in my car travelling at a constant 60 mph".
Re:It's spacetime, man (Score:5, Insightful)
Also, you're perception of the past is wrong. If I'm a light-year away from something and see something happening, I can say that in my reference frame, that happened a year ago. Someone travelling at speeds approaching c might disagree, but that's another story.
And a light-year is a measure of distance. If you specify "the time it takes for light to travel a light-year" than you have a measure of time, but that was not what the original story poster wrote (although you could assume it since the telescopes are recieving light).
Re:Distance Units? (Score:2, Funny)
it takes light from the sun about 8 minutes to reach our planet.
this means that the sun could have blown up 7 minutes ago, but it will still appear normal for about another minute or so.
then you will be toast.
regards,
sam
I would be happy (Score:5, Funny)
Re:I would be happy (Score:2)
Presumably if they can scratch your ass from space, they must be able to see your ass from space, so it sounds reasonable that it could see your ass from further away. If not, bring binoculars.
It's still past history (Score:5, Interesting)
Re:It's still past history (Score:5, Insightful)
Maybe there's nothing left (Score:2)
Overclocker point of view... (Score:4, Funny)
Nahh, I'll maybe void my warranty, but I'll just increase the fsb of my old Hubble...
Anyone has tips on deep space overclocking ?
Re:Overclocker point of view... (Score:2, Informative)
It gets exponentially more difficult... (Score:5, Informative)
As another poster has pointed out, it's actually a 3% improvement.
The point is, that's only 200 or 300 million years from the very beginning of the universe, and it gets exponentially more difficult the further back you want to see.
Rather than 13.7 vs. 13.3 billion years back from now, think 200/300 million years from the start versus 600/700 years from the start. That's a pretty good improvement.
Re:Overclocker point of view... (Score:5, Insightful)
Depends on how you look at it.
3 nines to 5 nines is
99.9% to 99.999% which is a
From the other end,
14-13.3 is 700M years after big bang
14-13.7 is 300M years after big bang
Better than 50% improvement (using Hubble as base)
Better than 100% improvement (using Webb as base)
The problem with percents is that they state one number and leave unstated the base for that number. Very little trickery is required to minimize or diminish importance without actually commiting falsehoods.
How do they know these numbers? (Score:3, Interesting)
Re:Does this mean... (Score:2, Interesting)
Look anywhere in the sky (after all, space itself has expanded from the point where it happened, so the big bang happened everywhere). There is still a faint glow. It has doppler shifted a lot, not due to motion but due to the expansion of the space it has travelled through. It's called the cosmic microwave background, and it causes a very small part of the interferance you can see on an untuned tv.
Re:How do they know these numbers? (Score:4, Informative)
the 1st one is called parallax (or triangulation) and consists on measuring the position of the star from different points of the earth's orbit (i.e., at different times of the year). The differences in the angular position are then used to calculate the distance of the object.
For objects (stars) that are too far away to give a measureable parallax (more than 400 light years), an indirect technique is used. It is known that different kinds of stars have different emission spectra (colors), and every kind of star has a characteristic brightness. This has been proven by observation of close stars. This way one can analzye the spectrum of a given star and guess how bright it should be. Since the light emission of a star is a spherical wave, the theoretical attenuation of its intensity can be used to calculate the distance. This does not mean that single photons lose energy on their way: they don't. A photon's energy is related with light's frequency (color), while the apparent brightness of the star is related to the number of photons that get here. Since thay propagate as the surface of a sphere, the further you are the fewer photons you get per unit area.
Re:How do they know these numbers? (Score:4, Informative)
BTW, this is where the term parsec comes from. An object in space is considered to be one parsec away if it appears to move 1 parallax-second in six months (when the the two observations are 2 A.U. apart because of the Earth's orbit). One thing that tends to confuse people about parsec measurements is that it's actually a reciprocal measurement. That is, an object that moves a 1/2 parallax-second is said to be 2 parsecs away, etc.
slight clarification.... (Score:3, Informative)
Lots of distance measures (Score:5, Informative)
Parallax is the method for the very shortest distances (nearby stars).
For intermediate distances (distant stars in our own galaxy, relatively nearby galaxies), most of the methods come down to finding some sort of "standard candle" - something that you know the intrinsic brightness of, so you can use its apparent brightness and the inverse square law to calculate its distance. Astronomers tend to use particular types of variable stars (stars with a well-defined cycle of brightness changes) for this purpose. For galaxies, you can sometimes use averaged properties of all the stars to estimate the distance.
For cosmological distances (very distant galaxies) the most common trick is to use redshift. Because of the universe's expansion, an object twice as far away is receding from us twice as fast, and so its light is Doppler-shifted twice as much. Ideally, you look for known features of the object's spectrum and see what wavelength they have ended up at. This is what people are talking about when they measure the distance to Hubble's latest find.
There is also a complementary method that uses standard candles at cosmological distances. In this case, you use Type Ia supernovae, a particular type of exploding star that looks pretty much the same every time. They're bright enough to be seen very far away, and again you can get the distance using the inverse square law (modified by general relativity). It's the difference between this method and the redshift method that provides the strongest evidence for dark energy - it shows us that the universe is expanding faster than we expect, and that this expansion is accelerating.
Re:How do they know these numbers? (Score:3, Informative)
Essentially both you and the parent are partly right. Redshift is a reasonable proxy for distance when you are sufficiently far away that your random relative motion (proper motion) is small relative to your Hubble expansion velocity. The problem is you have to know Hubble's constant very well in order to turn a redshift into a physical distance.
Thus there's a degeneracy where you
Re:How do they know these numbers? (Score:3, Informative)
There's a couple of parameters of interest here.
First of all, when you're looking at objects a looooong way off, there's a question of how many photons you get to collect from that object per unit time. If you collect too few photons, anything you might see gets lost in the noise associated with your detector (your 'camera'). You can see stuff further away with a bigger primary m
Does this mean... (Score:3, Interesting)
The BEST link on the Big Bang ... (Score:4, Informative)
Just for the record, the Big Bang theory is becoming as accepted in cosmology as the theory of evolution is in Biology.
There will eventually be a limit to how far back we can look in time. The Big Bang itself will just appear to be an incredible brilliance everywhere.
That same brilliance has cooled to the point that nowadays, it's only detectable as an almost-universal background microwave radiation.
The detection of that radiation is considered one of the strongest "proofs" of the Big Bang theory, by the way.
Re:The BEST link on the Big Bang ... (Score:2)
So this will be an other theory that will not be taught in schools. I always find it funny how people confuse religion and science. And the "religious" people are picking over the details of their religion and not getting any of the true meaning.
Re:The BEST link on the Big Bang ... (Score:3, Informative)
I'm being pedantic but....
Its the idea that there was a Big Bang that is accepted by almost everyone, but there is no single universally accepted theory of how the Bing Bang banged and what happened afterwards. Did inflation happen? Did the speed of light change? Was the Bing Bang a singularity? Was there one Big Bang, or several? All these are subject to debate.
Re:Does this mean... (Score:2)
We can only hope to detect the effects of the big bang on parts of the universe that have been moving away from us
Re:Does this mean... (Score:5, Informative)
John Barrow's book "Impossibility" has a nice description of this (and other limits).
Re:Does this mean... (Score:2)
Re:Does this mean... (Score:3, Informative)
Nope. In the very early Universe, all the matter was so hot that it was completely ionised. That is, there were lots of protons flying about and lots of electrons, just doing there own thing. It turns out, that light interacts very strongly with free electrons, so any light that was around at this early stage (such as from the big bang...) would've bounced around so much that it no longer carried any useful information about earlier times. Kind of like tryin
Re:Does this mean... (Score:3, Interesting)
Pretty much everyone in the class said True. The instructor marked it wrong. His explaination was that there would have been so much heat generated during the big bang that the energy wouldn't be
Re:But hasn't light overtaken us long time ago? (Score:4, Insightful)
You're imagining the Big Bang as an explosion taking place in space. In this view there is an infinite, empty expanse of space, in which there is an explosion at one point which throws out all the material in the universe.
This view is wrong. If it was correct the galaxies would form a roughly spherical shell around an empty central region, at the very centre of which would be the Big Bang's 'ground zero'. We would therefore expect to see a great clustering of galaxies when we looked along the surface of this sphere toward our neighbours, and a great empty darkness 'above' and 'below' us. But this is not so; in fact the galaxies are very evenly distributed throughout all of observable space.
The Big Bang is more correctly viewed as an explosion of space, rather than in it. The Big Bang takes place simultaneously at all points in space, and it is space itself that expands thereafter, spreading out the contents of the universe and cooling the hot gas.
As a result, the light emitted from our region of the Universe in the Big Bang has indeed long since left the area, but we are now able to see the light emitted from the Big Bang in regions that are now some 13.7 billion lightyears away. Of course at the time they were much nearer than that...
We have, in fact, seen the Big Bang, or at least seen as close to it as we can ever hope to achieve. In the very early stages of the Universe, light could not propagate far; the universe contained a hot, dense gas of charged particles which was opaque to light. Once the electrons and protons combined to form hydrogen atoms, the gas became transparent and the light was released. This light has been greatly redshifted by the enormous expansion of space, and is now detected as a background glow of microwaves at a temperature of about 3 kelvin.
Not mentioned in the article... (Score:5, Informative)
http://en.wikipedia.org/wiki/James_Webb_Space_Tel
http://en.wikipedia.org/wiki/Hubble_Space_Telesco
Grr...
A sceince question... (Score:2, Interesting)
I know many people here are better at science (not to mention spelling, grammer, coding, e.t.c), than I am, so i ask does this not make a lot of these predications less accurate than they might think?
Re:A sceince question... (Score:5, Interesting)
Short answer no, longer answer we don't know. Pretty much all of modern physics is built off the idea that the speed of light is a constant. If you start changing the speed of light then all sorts of thing "break" like conservation of energy. So if you can change the speed of light, you could create matter out of nothing. Neat trick if you could pull it off. That said changing the speed of light does solve some nasty problems [amazon.com] surrounding the big bang.
There's also the question that if the speed of light was changing if we'd even have any way of noticing because everything would be skewed along with it. Fun stuff.
Re:A sceince question... (Score:2)
Re:A sceince question... (Score:2)
Technically it would have been his third mistake. There is some redundancy in the first 'sentence'
"I'm not a that great with science,"
cheers,
Seeing to the beginning? (Score:3, Insightful)
Re:Seeing to the beginning? (Score:5, Informative)
Re:Seeing to the beginning? (Score:5, Informative)
I say stop it immediately (Score:5, Funny)
Some of us prefer the universe the way it is, more mature and filled out. I think its disgusting that these perverts want to spend so much money to ogle at the universe when it was a young hottie.
No doubt they are also hoping to get a glimpse of some of the banging the universe got up to in the exuberance of youth.
Shame on you all I say.
Yours etc.
Outraged
Orbit and location? (Score:3, Interesting)
-J
Re:Orbit and location? (Score:5, Informative)
Re:Orbit and location? (Score:4, Insightful)
(I understand the logic, but I really like contingency plans...)
Re:Orbit and location? (Score:2)
Re:Orbit and location? (Score:2, Informative)
Any service missions would need to be entirely automated, which probably makes them impossible.
Re:Orbit and location? (Score:5, Informative)
Running Webb at L2 will save money. It's difficult and expensive to run a large space telescope in low Earth orbit (LEO). Observations have to be planned carefully since the Earth gets in the way for most of the sky every 90 or minutes. The satellite also has to have batteries to power the systems when the satellite/telescope is eclipsed by the Earth. Batteries are heavy, have to be recharged and they fail. Hubble's are failing. Large satellites in LEO slowly see a degeneration of their orbits because of drag from the very highest parts of the Early atmosphere. This requires them to be reboosted very so often. Any future service mission to HST needs to also reboost it.
Finally, satellites in LEO - least ones in orbits like the one HST is in - have to travel through a radition belt every orbit that can cause electronics to fail and bits to flip. This sometimes causes the telescope to go into safe mode and ruins observations. While in safe mode, operations crews are standing around and more observations have to be either cancelled or rescheduled.
Many of these problems are avoided at L2 or similar locations. Webb's life will be limited by the amount of sensor coolant on board, but space telescopes like the International Ultraviolet Explorer [etsu.edu] have operated for 20 plus years. IUE used a small crew, was easy to operate and produced more then 3,000 papers at a very low cost - a great return in value for tax payer.
Re:Orbit and location? (Score:3, Interesting)
Hubble is open source (Score:2, Insightful)
Half the lifetime for the same cost? (Score:3, Insightful)
Surely modern manufacturing etc should be able to improve on Hubble's lifetime for the same money? What am I missing?
Re:Half the lifetime for the same cost? (Score:5, Informative)
Looking at the past... (Score:3, Insightful)
Re:Looking at the past... (Score:3, Insightful)
13.3 vs 13.5, correcting numbers? (Score:2, Interesting)
Time vs distance (Score:2, Interesting)
Re:Time vs distance (Score:2)
What if... (Score:2)
Re:What if... (Score:2)
Oh god, does that mean I'm gonna have to go through high school, over and over again?
position in space (Score:3, Interesting)
Servicing missions to the Hubble added about 4-5 years of operational life to the telescope and this was possible because being only a couple of hundred miles above the earth, it was accessible.
Obviously, we are human and we can make mistakes. So what happens if there is a problem discovered on the Webb telescope after its launch?
Re:position in space (Score:2, Funny)
Orbit, Hubble, Optics, and a question. (Score:5, Informative)
The orbit is about 1.5 million km distance from the earth, at something called the L2 Lagrangian. The Webb wiki page has a link to the Lagrangian page, but for the lazy people, it's here [wikipedia.org]. The orbit was chosen to keep the position of the sun constant relative to the telescope, so that the big 'parasol' can be used to shield the infra-red sensor.
As for Hubble, it's been able to give some awesome images, but it has its limits. I was hoping that the JW (henceforth called J-Dubya?!) would be able to start spotting planets around other stars, but it's not designed for that. I'd like to know if it's theorically possible to keep both in orbit and use them in parallel somehow, in the same way that ground-based radio telescopes have been linked together in arrays. Probably not worth the hassle?
The 'infra-red only' sensor troubles me. Since the telescope's aim is to study the Big Bang, the light/photons it'll be receiving will have travelled for a long time/distance and I guess be red-shifted way down to the IR band. This is all very well, but it means that the telescope shouldn't be considered as a replacement for Hubble, which carries out a wider range of observations.
As an aside, I believe that there is a limit to how far back we can look. At some point, probably less than 1 million years (a guess, can anyone help?), the universe was just too dense for photons to travel around unhindered as they seem to these days. Who said it was better back in the old days eh?
Now two questions. First why beryllium? I know that it's lightweight so easier to lift into orbit. Any other reasons? And secondly what happens if a micro-meteor hits this shield? Do we get a permanent bright spot on all subsequent images, like a broken pixel on an LCD display?
One catch (Score:2, Insightful)
Nope (Score:2)
Webb won't be riding the shuttle (Score:3, Informative)
How Does that Work? (Score:2)
If this is the case, what do we get by pointing our telescopes toward the center? Is there some crazy ball of energy still expanding outward or something? (Assuming the big bang theory is right.)
Oh yeah, I assu
Re:How Does that Work? (Score:5, Informative)
It's important to remember that at the moment of the big bang, there wasn't a universe outside of it. That is to say that when the big bang occured, it didn't expland into some already exisiting space, rather it was the space that was expanding. As such, all objects are moving away from all other objects.
http://www.astro.ucla.edu/~wright/nocenter.html
has a decent drawing to illustrate how this leads to no "real" center.
The other explanation that has always helped me picture it is to imagine the universe as an un-inflated balloon. In this model, we've reduced the universe to a two-dimensional, unbounded, infinite space in order to help us visualize this principle. Before inflating the balloon, mark several points with permanent marker, Now, when you inflate the balloon, you can see that each point grows more distant (over the surface of the balloon) from every other point you've marked and that the farther one mark is from another, the faster it moves away from it. From the point of view of a given mark, everything else is moving away from it, which would give the impression that it's at the "center" of the balloon's surface. At the same time, however, that impression would appear to be true for every other mark.
Obligatory Star Wars reference (Score:2, Funny)
although (Score:3, Informative)
In that sense, it's implied in almost ALL astronometrical comments like "we saw this 15 light years away"; it's are really saying "we saw this event happening 15 years ago because that's as recent as we can see anything from that target".
So yeah, basically you're right, but it's faintly arguable.
They just don't make things like they used to... (Score:3, Informative)
I'd have expected a more recently built telescope to last longer than an older one.
Also, anybody have a clue exactly what happens when a telescope dies?? (Visions of Hubble slowly growing incontinent etc.....)
Re:Uh. (Score:5, Informative)
Re:Please explain (Score:3, Informative)
Re:Uh. (Score:5, Interesting)
as it is, knowing what the universe looked like at age 300Million is quite nice by itself and simply saying that it "ain't nuttin' new" is quite ignorant!
as the light has traveled millions of light years, we ARE actually seeing something that existed millions of years before our time and thus you could call it some kind of "looking into the past"!
Re:Uh. (Score:2, Interesting)
Re:Uh. (Score:2)
light speed in diferent materials (Score:3, Informative)
Light can slow down. In an open vacuum it is at it's highest speed. Going through materials it slows down a little. The speed change is different for different materials.
An example is that light slows down going though glass.
Re:Time Distance? (Score:2)
The events happened that many years ago, and that many light years away.
A News for Nerds site should get such basic science concepts right.
Re:Time Distance? (Score:2)
Of course it's more fun when you start thinking in four dimensional space-time, instead of three dimensions, and the bending of light due to the gravitational force of extremely heavy cosmic objects (including black holes). For example, astronomers can sometimes see distant stars that ought to be masked by nearer objects such as the Sun. Instead of travelling in straight l
Re:Web site rip off (Score:3, Informative)
Re:Perhaps someone can explain... (Score:4, Insightful)
The important factor is collecting enough light from a very faint source.
So the area of the mirror, the sensitivity of the camera and the directional stability of the system over time are what counts.
Re:Do we know where to look? (Score:5, Informative)
When you look away from the earth, you are looking back in time. This is due to the fact that photons travel at the speed of light. So if you look at the moon, you see the moon a half a second ago. Mars is several minutes ago. Alpha Centari is about a year ago. So the futhrer out you see, the further back in time.
Now think of the universe as expanding. If you look out a to a distance where the light is half as old as the universe, you see the universe as it was at that time. But the universe was much smaller then so the galaxy you look at seems bigger than it should given how they look today. So the expansion of the universe and the traveling of photons acts as a lense making things look bigger as you look back further (theres less universe to fill the sky so objects look bigger).
OK so then you look all the way back. The big bang then fills the sky. It is everywhere. And we see it. Its what is refered to as the 3 degree Kelvin background radiation. And in the radio, no matter where you look, you see it.
Now this is not actually the big bang itself. The universe was too dense for anything to be seen. So what we see is what is referred to as the universe at the time of last scattering, when the light from the big bang was finally able to escape as the universe had expanded enough that it was not so dence to capture all the light. So when you hear about people studying the fluctuations in the background radiation, they are actually studying this period of the universes expansion.