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BOSS: The Universe's Most Precise Measurement
Cazekiel writes "Observing the primordial sound waves created 30,000 years after the Big Bang, physicists on the Baryon Oscillation Spectroscopic Survey have determined our universe's most precise measurements: 13.5 billion years old. The article detailing the study reports: '"We've made precision measurements of the large-scale structure of the universe five to seven billion years ago — the best measure yet of the size of anything outside the Milky Way," says David Schlegel of the Physics Division at the U.S. Department of Energy's Lawrence Berkeley National Laboratory, BOSS's principal investigator. "We're pushing out to the distances when dark energy turned on, where we can start to do experiments to find out what's causing accelerating expansion."'"
...like a boss.
...or so I've been told.
The scale of this survey is really quite incredible. It will serve as a benchmark for other accomplishments for years to come.
For example, I just made a remarkably roundabout pop culture joke...
How can I believe you when you tell me what I don't want to hear?
Isn't Slashdot supposed to be News For Nerds? Oh wait, it probably doesn't get any more nerdy than this. Good stuff.
It says the universe is precisely 13.75 billion years old, not 13.5 billion years old.
Shoes for Industry. Shoes for the Dead.
I always try to get my head around the meaning of measuring something in units which didn't exist then.
While this project may yield a lot of data it still won't be able to answer most of the fundamental questions. I know they have to advertise that way in order to receive sponsorship and grants, but dang it I'm tired of hearing it.
We still won't have a clue about what Dark matter is, or even if it exists. It's still a hypothesis that makes big bang models work and gives us the idea that we understand gravity.
We still won't know what the Universe was just before the big bang, or what caused it.
Cool, but I'll ignore the hype.
-The wise argue that there are few absolutes, the fool argues that there are no probabilities.
The title meant to say "BOSS: The Most Precise Measurement of the Universe". The other way round can mean these measurements are the most precise ever, which isn't even remotely true. For instance, the article says, "BOSS gives that distance to within 1.7 percent", whereas (to pick something out of a hat) the fine-structure constant has been measured to a precision of less than one part in a billion or within less than 0.0000001%.
Maybe a physicist can chime in here--how is the red shift actually measured in an experiment like this? You could of course measure the wavelength of incoming light, but how do you know what the wavelength "should" be? Are there some common spectral lines one can look for?
Also, is there any practical use to this experiment? I'm fine with pure research, but I was curious if maybe some of the techniques find application elsewhere. The article didn't mention any.
it's einstein's relativity 101. no event "appears" simultaneous to two observers moving at different speeds.
there fixed that up for you...
That would be like saying 'since I cant see it it didnt happen'...
Obviously it's saying that no-one in the entire universe has ever measured anything to more than three significant figures.
No it isn't, you're making a common mistake that people who pretend they know about physics make. Put it this way: leave the physics to the people who know anything about it and go back to masturbating over furry porn.
Cosmology is based on the Robertson-Walker metric. The Robertson-Walker metric contains an unambiguous time coordinate. Put an observer in that metric and, yes, they will observe a different time -- but if they're not to violate the symmetries of the metric, the differences will be at a perturbative level, which is to say unimportant. When they say "the universe is 13.7bn years old" they don't mean to say "the time measured along every worldline would give 13.7bn years", because to say such would be nonsense. What they mean that "the time measured in a frame comoving with the metric is 13.7bn years and to an approximation good up to redshifts of approximately z=1 and quite possibly significantly less this is an estimate that holds for all observers who haven't gone dallying with black holes".
Seriously, learn what the fuck you're talking about before you make yourself look stupid.
I'm sure that people who have studied cosmology, both theoretical and observational, in extreme depth, for a period of upwards of 20 years, are going to be devestated that "Proudrooster" and "decora" on Slashdot have shattered their entire field with a few brief sentences. Such a waste of man-hours! I'm sure the two of you will be quick to provide us with alternative models of cosmology and interpret them properly for the layman, causing no ambiguities in those who don't fully comprehend the fruits of your genius.
Seriously, "a headline grab"? This is the ninth data release of a massive project that's been going for more than twenty years since it was first planned in detail, it's been studied by hundreds of extremely well qualified physicists, astronomers and engineers, and is providing data for all of us in the field to use to test models which we construct, from which we extract observable parameters, and test against observation... and you think it's a fucking headline grab? You think it's arrogant? The mind fucking boggles.
Thought this was going to be about a Stones concert tour.
Never mind.
Have gnu, will travel.
Why do we use years as time measurement for events that happen in the universe? Years are an Earth measurement that have no bearing on anything else in the universe.
with the universe full of 'dark matter', how do any of us know that our bits havent been dallying with black holes?
It says the universe is precisely 13.75 billion years old, not 13.5 billion years old.
... the universe is actually 13.74892103652974083 billion years old, and counting ...
Muchas Gracias, Señor Edward Snowden !
The press releases linked to from the /. summary are pretty thin. The Wikipedia article
is a lot better. Here are the two papers: [1], [2].
Find free books.
I assume that when the universe started there was only one reference point, the origin.
it's einstein's relativity 101. no event appears "simultaneous" to two observers moving at different speeds.
Ok, but we are discussing 10^87 observers that are all moving at the same speed (C)
therefore there is no such thing as the 'beginning of the universe' common to all reference frames.
Therefore if you start with proven incorrect assumptions, you will only get proven incorrect answers.
Worst summary ever.
Welcome to slashdot. I hope you stay a while.
It's pretty obvious, just people aren't thinking about it from the right mindset:
It has to do with the expansion of outer shell of the edge the remnants of the original big bang explosion; It's really a type of a 'less resistance' problem, like as if something like air resistance gets less as the perimeter of the expanding explosion moves out, yet the mass of the universe remains the same. [Although that explanation ignores the fact that there's not a whole lot of air in space, but bear with me.]
Although it's not a normal resistance issue like the basic effect of wind resistance, it is different but similar enough to make the full point of view as follows:
Sort of easy to describe using an analogy of a balloon inside of a large bell jar. Normally, when you blow up a balloon, the air pressure increases as the balloon expands, since it's the increasing air pressure inside the balloon which is causing the expansion.
But in this case, blow the balloon up halfway, tie it, and seal it inside of the bell jar. Now you sharply/quickly reduce the air pressure in the bell jar by somehow removing a volume of air that is just less than it will take to pop the balloon by over-expansion as the air pressure drops. (Not sure of the math to determine that amount, just would have to experiment with a few balloons to get it right. It's not important to get it at the edge of popping, it's really what goes on inside the balloon while it's being inflated so quickly, yet this time with air pressure decreasing rapidly as it expands rapidly.
With the impetus coming this time from the outside of the balloon with the bell jar causing a sudden 'vacuum' (Violent loss of pressure actually, not a true vacuum.) implosion around the balloon instead of increasing the pressure on the inside of the the balloon. With the sudden change in outside air pressure, due to the elasticity of the air inside the balloon it would cause a donut-shaped compression wave to (Is there a word for three-dimensional equivalent of the act of traveling from the outer to inner rings of a set of two-dimensional concentric circles?) intensify as it shrank to a more and more compact size, then impacting itself as it reached the absolute center of the balloon, causing it to violently bounce as a shock wave radiating outward to the edge of the balloon, where it's energy would suddenly press against the edge (Yet the force of the sudden re-expansion will cause a 'vacuum ball' of lower pressure in the center of the balloon caused by the bounce causing a lot of air particles in the center to bounce out with the shock wave as they attempt to reclaim the natural equilibrium between air particles), causing it to expand a bit as the rubber/latex gives way a bit (Yet still not popping) and then de-expanding (starting to shrink) as the energy of the shock wave is spent fighting the elasticity of the balloon's edge and then loses.
Next we get it in reverse, and over and over until all the energy from that initial shock of 'vacuum' has been converted to friction/heat. But that entire process of bouncing is still not the part we are focusing on, but we're nearly to the end of this long explanation:
Now think of the particles of air inside the balloon, and how they would react as to their average distance between particles, both expanding and compressing. During the phase where the shock wave is expanding back out after it's first collision with the center, about halfway between the center and the edge of the balloon - the energy of the shock wave has already caused some of the inner air particles to begin traveling outward and gaining some inertia. While at the same time, the edge of the balloon is still rapidly receding as it expands due to the 'outer vacuum' of the bell jar still loosing pressure and 'sucking' the balloon larger.
So this sets the particles moving outwards, and if you do the math - all particles are moving away from each other at an increasing speed, just like the particles/energy of the universe are doing as it expands outwards from the core of the big bang explosion.
Ok.. I just updated Wikipedia. The Universe is now 13.5 billion years, it was at 13.7.
Hah, that's extra funny considering the summary's 13.5 billion number came from misquoting the Discovery article's link to an older article (by another group even) titled The Universe is Precisely 13.75 Billion Years Old. You and the submitter might hit it off nicely--you'd at least be able to talk about your remarkable lack of attention to detail.
I'm pretty sure you're joking about editing Wikipedia, but really you have no idea what you're talking about. Being confused by time dilation is for undergraduate physics majors. The world is unintuitive. You get over it after a while; all that matters is that you can make accurate predictions about it, and time dilation does not violate that ability no matter how much cognitive dissonance it causes you.
About something that was 8 orders of magnitude longer in the past than my own life expectancy. Well, I do not begrudge these people their intellectual exercise, I just hope they did not spend a lot of money on this irrelevant result.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
"We've made precision measurements of the large-scale structure of the universe five to seven billion years ago"...
And they're just now getting around to telling us about it?
You make it sound like it would be a noteworthy feat if someone attempted the task and had some measure of success.
If they don't exist, do your mod points really matter at this time?
I was promised a flying car. Where is my flying car?
One does not simply play guitar in the Rolling Stones?
I was promised a flying car. Where is my flying car?
"We've made precision measurements of the large-scale structure of the universe five to seven billion years ago" - Sure took you long enough to get the news out.
Was the primordial sound aum? http://en.wikipedia.org/wiki/Om
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I believe this is where one says "Wooooosh"
there could be black holes in the dark matter. that's the whole point - we don't know whats in it?
are moving at c? that seems like a big assumption to me.