Tag Archives: Cosmology

What’s at the edge of the universe?

Gizmodo has an interesting article that someone asked my thoughts on.  Part of their “Giz asks” series, it asks various physicists what’s at the edge of the universe?  The physicists polled include Sean Carroll, Jo Dunkley, Jessie Shelton, Michael Troxel, … Continue reading

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Dark energy and repulsive gravity

Over the weekend, Sean Carroll put up a blog post to address common misconceptions about cosmology.  I understood most of his points, but was confused when I saw this one: Dark energy is not a new force; it’s a new substance. … Continue reading

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97% of the observable universe is forever unreachable

The other day, I was reading a post by Ethan Siegel on his excellent blog, Starts With a Bang, about whether it makes sense to consider the universe to be a giant brain.  (The short answer is no, but read … Continue reading

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Dark energy may be less energetic than previously thought

This is interesting.  Astronomers discovered dark energy, the energy causing the rate of expansion rate of the universe to speed up, by looking at large numbers of Type 1a supernovae. Type 1a supernovae are white dwarfs (collapsed stars after their … Continue reading

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Half the stars in the universe may exist outside of galaxies

Every so often you get a reminder of how little we know about the universe: Rogue stars outside galaxies may be everywhere | Science/AAAS | News. You’ve heard of rogue planets, floating through the universe untethered to any solar system. Now … Continue reading

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Multiverse theories: “meta-cosmology”?

Marianne Freiberger reports on a discussion she had with Bernard Carr on whether or not multiverse theories are science.  He has a suggestion for how we should classify these theories. With the possibility for indirect evidence in the future, maybe we … Continue reading

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Jim Holt: Why does the universe exist?

I did a post a few weeks ago explaining why I’m not much of a fan of the “Why is there something rather than nothing?” question.  So, when this TED talk popped up later, I resisted watching it, thinking it would … Continue reading

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The size of the observable universe is complicated.

The radius of the observable universe is often stated to be 46 billion light years.  From a certain point of view, this is true, but I think it’s a bit of a misleading statement.  Occasionally you also see people say that … Continue reading

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BICEP2 team publishes results, backpedals on certainty

The BICEP2 team have officially published their results.  They had announced to much fanfare back in March, that they had detected primordial gravitational waves, and hence cosmic inflation.  But the results have increasingly been met with doubt, primarily centered on the possibility … Continue reading

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Pseudophysics: The New High Priesthood

Wow.  Somewhat in balance to yesterday’s reblog of part one of Coel Hellier’s post defending multiverse theories as scientific, here’s Amir Aczel skewering many of the proponents of multiverses and other untestable cosmological theories.  He takes aim at Brian Greene, Max Tegmark, … Continue reading

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