Back in December 1995, the Hubble Space Telescope created the now-famous “deep field” image, which took more than 300 exposures over the course of 10 days to peer deep into the history of the universe and spot more than 1,500 galaxies. A decade and a half later—after failures, upgrades, and the “ultra deep field“—Hubble marches on. Yesterday at the American Astronomical Society meeting, astronomers announced they’d used the telescope to look deeper into the past than ever before.
The new image captures 7,500 galaxies of all kinds and shapes. The oldest galaxies in the image glow an intense blue, indicating high concentrations of the lighter elements hydrogen and helium. Hydrogen fusion inside active stars creates heavier elements such as iron and nickel, which get spread across the universe when massive stars explode. These elements cause modern galaxies to glow in a rainbow of colors, so the extreme blueness of the newfound galaxies suggests that they formed before very many massive stars had lived and died [National Geographic News].
The ancient galaxies are also tiny by galactic standards, containing just one percent of the mass of our own Milky Way galaxy. But they could play an important role in showing astronomers how galaxies formed as the universe aged. These galaxies started forming just 500 million years after the big bang, which is thought to have occurred around 13.7 billion years ago. That pushes back the known start of galaxy formation by about 1.5 billion years [National Geographic News].
Hubble captured this newest image with its Wide Field Camera 3, a new piece of equipment that the last space shuttle flight to upgrade the telescope installed last year. But unanswered questions remain. The big mystery is the era when ultraviolet light from the youngest stars electrically charged early clouds of interstellar gas, triggering magnetic effects that played a role in later galaxy formation, says astrophysicist Mario Livio…. This “re-ionization” era probably played out just before or during the time when the lives of the early galaxies turned up in the new Hubble images [USA Today]. Hubble’s would-be successor, the James Webb Space Telescope, could help sort out this era’s history when it launches in 2014.
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80beats: A Hot Piece of Hardware: NASA’s New Orbiter Will Map the Entire Sky in Infrared
Cosmic Variance: Well, That Was Fast, on the upgraded Hubble’s initial data
Bad Astronomy: Hubble’s Back, and Spying on Wailing Baby Stars
Image: NASA
January 6th, 2010 at 12:12 pm
This is probably an idiot question from only a dabbler in physics, but it tends to puzzle me at times.
Given the Speed-of-Light limits, how did WE get “Here” before the light from these distant (and ancient) galaxies?
Thanks!
January 6th, 2010 at 3:35 pm
Thank you for asking this question. I wouldn’t even consider myself a dabbler in physics, more just someone who’s interested in science, but that is exactly what I’ve been wondering about. And you stated the question much more succinctly than I could have. I hope someone posts an explanation or points us to an article that explains this.
January 6th, 2010 at 3:46 pm
I’m no physicist , either, but here’s a go. It all depends on the space the light from the galaxies traverses to reach us.
If a light source is 13 billion light years away AND 13.2 billion years old, then it’s light has been visible for 200 million years (before “WE” existed).
If it’s 13.7 billion light years away and 13.2 billion years old then it’s light won’t reach us for another 500 million years, meaning we were “here” before the light was to reach us.
Those galaxies must be closer to us (in light years) than they are old, in order for their light to be present here.
In order for the same galaxy’s light to have reached Earth’s current location in space before EARTH existed then it must be less than 8.7 billion light years away, given the age of the Earth is 4.5 billion years. (13.2-4.51= 8.69)
I don’t know…. I think you guys might be complicating things.
Are you asking how matter reached our point in space before the light did? You’d probably need the coordinates (everywhere) where the Big Bang transpired to know. Once again, it depends on space and time, not just time.
Please don’t be too harsh.
January 6th, 2010 at 3:50 pm
I’m also a dabbler at least in cosmology but from what I’ve read and gathered there seems to be a common misconception that the big bang occurred at a point in space then spread out in a sphere – like a firecracker exploding. The counterpoint is that time and ‘space’ just did not exist before the big bang. The big bang happened everywhere at one instant – on our side of the universe as well as the other side – 13 billion light years away where we are just now receiving the light. Now if there are creatures at that end of the universe looking in our direction, they would be viewing the Milky Way as it appeared in the beginning.
January 6th, 2010 at 10:51 pm
I personally don’t buy this “black box” of suspending nasty little laws of physics just because it may prove us wrong…
The universe is expanding. It is going from point “A” to point “B” and then to “C”. That means since it’s going somewhere, it came from somewhere. Since we are getting farther apart, to reverse this effect leads to all of the universe at some time back in the past being in one space.
So, unless you insert a magic black box labeled: “Well, of course the laws of physics can be suspended when they become bothersome.” the answer is that we don’t know. We need to refigure…
So, IMHO, there are things we are not seeing and taking into account since we haven’t had enough time to get 13 billion light years from anything unless you suspend the laws of physics.
January 7th, 2010 at 10:24 am
No matter which direction we observe, we see expansion of space, so the likely conclusion is space is expanding everywhere – not from some center of the universe. Otherwise you have to believe that we on earth have been given a very special privilege of being placed at the center of the universe. Whats the chance of that? The whole concept of ‘space’ at the point of the ‘big bang’ is inconceivable by today’s concept of space. What we observe today unfolded from that inconceivable singularity.
Hubble and other technologies have allowed us to gather data far beyond our previous observational capabilities and the data are not fitting the model based on Einstein’s theories. Either the constants in the model are wrong or the structure of the model itself is wrong.
January 7th, 2010 at 2:35 pm
Ok, the question is being over complicated. You are asking how we got to our point in the universe to see light that is older than we are basically.
Ok first you have to stop thinking about the age of the earth. It is irrelevant. After the big bang, matter was expelled from one point (theoretically) expanding in separate directions. That matter, if producing photons, was expelling those photons in separate directions constantly from the beginning. So we have been receiving this light since the beginning of the universe. Or the matter that was to become Earth was intercepting these photons.
Since we could be moving in direct opposite directions away from each other the photons take longer and longer to get to us. But that continual stream of photons was still reaching us and traveling in a path that we would intercept it even if we are not existing at that time giving us the opportunity to see it.
We are just constantly moving into a position that intersects the photons from earlier in time to become visible.
Now to really throw a wrench into this, how do we know that the photons we are observing are in reality 13 + billion light years away? Or that the photon we are seeing was originally in the position we see are observing it. How do we know that the photons we are observing are not really 8 billion light years away and they passed by so many black holes and other high gravitational objects that the photons were slowed enough that it took that much additional time to reach us. Or though outside gravitational forces didn’t change the photons path, even by just sub nanometers, which over billions of years actually skew the actual position of these galaxies by thousands of millions of miles?
January 7th, 2010 at 5:09 pm
Ikaiyoo: The photons we are seeing are not 13 billion light years away. They are here and now. They originated from their luminous source 13 billion years ago from the other side of our observable universe.
I don’t believe we know if those photons have been affected by gravitational perturbations – unless we can detect effects like gravitational lensing along with the observation. But I also believe the measurements are averaged in all directions we can be fairly confident of the 13 billion year figure.
Any veteran cosmologists out there that want to pipe in?
January 8th, 2010 at 8:25 am
Mike: Thank you for correcting me.
The last part of my comment I wrote hastily after conversing with a co-worker who after reading the initial comments was asking me if I understood what the original poster was asking and the replies that followed. But you get the gist of what I was saying. I did not mean 13 billion light years away but how do we know that they are infact 13 billion years old.
And I too believe that yes they are more or less correct in the 13 billion estimate. I just thought it was something that would be interesting to point out and have people ponder on.