Links and Comments: The Size of the Universe; The Size of the Planets

» NPR’s blog Cosmos & Culture: Lessons From The Beginning Of Time.

One report, among many in the past few days, that the apparent detection of ‘gravitational waves’ from the Big Bang, a year ago, was a false alarm: the evidence is explained via mundane intergalactic dust.

That’s fine; this is how science examines and corrects itself. This post is nice in summarizing the many things that *have* been firmly established about the size and age of the universe.

We should take note of what we do know about the early universe, which is nothing short of spectacular. We know that the universe is about 13.8 billion years old (a number that, updated from 13.7, has given us pause about the name of this very blog). We know its composition, or at least the relative contribution of the ingredients — if not the ingredients themselves (dark matter and dark energy remain a mystery). We have a firm grasp of the cosmic history from 400,000 years after the Big Bang to now — and we can even push it earlier, to a minute or so after the event, when the first atomic nuclei were synthesized. We also understand how galaxies form and how they are distributed across space, even if we still don’t know where the seeds that leapfrogged their emergence came from.

We share with our ancestors the urge to understand our origins, to unveil the mystery of creation. The fact that science opens a window for us to peer into our deep past should be a cause for celebration, irrespective of what we find when we are finally able to look.

At Slate a couple days ago, Phil Plait asks Can You Really Fit All the Planets Between the Earth and Moon?.

He’s responding to a claim in a cool viral video called 209 Seconds That Will Make You Question Your Entire Existence, which suggests that, given the sizes of the planets, and the distance between the Earth and Moon, you could fit all the planets in that gap.

It’s pretty much true; Plait quibbles here and there, but it’s mostly true.

To me it’s an example of how our intuitive grasp of sizes and distances offers no clue to the truth of this claim. Put the numbers together, and they substantiate the claim. More remarkable are those comparisons of the distances between the planets, and the sun, compared to their sizes…. a basketball 500 yards to an apple, a mile to a pea.

(File this under Provisional Claim #2.)

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