never mind, the universe is still probably expanding at an accelerating rate

On further review, the study claiming that the universe is expanding at a steady rate ended up independently proving accelerating expansion.

galaxy edge on

Not too long ago, I did a writeup on a study that claimed to show evidence that the universe's expansion is not accelerating based on an analysis of a larger dataset of Type Ia supernovae than previously done. Like every pop sci writer and ex-grad student, there was a lot of hedging of bets and ifs in the post, and it turns out for good reason. While I can claim some sort of an academic credential, my field is computer science, not astrophysics, so when an expert on the subject reviewed the same study, he found it lacking.

The problem? Using redshift, or the distortion of light due to distance, from one consistent supernova type (see the first link for details on why we use Type Ia supernovae for this research) is a great start, but there are more things we know about the cosmos that limit the the results's potential impact. Basically, we plot the supernovae data and analyze how well they match the predictions of how they should line up according to certain models of what we think the universe looks like, and the study in question found that there was not much difference in the observations between the fit for a constantly expanding universe and one for accelerated expansion.

But since we know a lot more about the universe than just where stars explode and with how big of a bang, we can focus on the difference between the error bars to tighten up the model with what we know. When we account for the known mass of the universe, which we know we have right, we limit the probabilities to a certain range within which we know the model works. We can limit the fit even more by considering that the universe is flat. And when we do that, we end up with the paper's results neatly falling in line with the accelerating expansion model because the other models involve violating what we know about the universe's shape, mass, and overall density to work.

So does this mean the paper challenging the consensus was a waste of time or a failure on the researchers' part? No, not at all. In fact they were able to independently offer additional proof of existing research and even with very skeptical eyes, starting form scratch, with a new, larger dataset, end up with very similar conclusions as other researchers, conclusions that fit well with the rest of the data we have about the universe and can be tightened by two undisputed observations about our cosmos.

This means we're still stuck with dark energy and need to figure out what it is, but these results are just more proof that it's real and we're not getting rid of it anytime soon because there is no way to explain our observations without out. Even if the study showed constant expansion, the fact that we can't get rid of the expansion in any of our analyses shows that there's an unseen force driving the basic mechanics of our entire cosmos. And we now know for sure that it's driving it to grow faster and faster…

  archived from wowt
              
# science // cosmology / dark energy / physics


  show comments
latest reads

how to endanger the future of space flight for status and profit

CEOs and space faring powers are treating low Earth orbit as their personal playgrounds, much to the horror of space agencies.
how to endanger the future of space flight for status and profit

why your boss is obsessed with a.i. past the point of sanity

Not only is the C-suite not immune to AI psychosis, they seem to be primed to suffer the worst of it as their employees duck and cover.
why your boss is obsessed with a.i. past the point of sanity

why so many of us are just not that into chatbots

AI adoption is at an all time high, but opinion of AI keeps on tumbling with every poll and study on the subject.
why so many of us are just not that into chatbots

no, your chatbots aren't secretly marxists at heart

But they can and do detect and complain about unfair treatment when asked, according to an experiment by Stanford researchers.
no, your chatbots aren't secretly marxists at heart

how the right wing took over social media

Right wing content has a major advantage on social media. But we can do something about that with a very simple change in our habits.
how the right wing took over social media

no, we still don't know why t. rex had little arms

Popular science outlets continue to do a terrible job of explaining studies on primeval evolution and pretending we have answers we don't.
no, we still don't know why t. rex had little arms