Physics at the Universe’s Limits (Synopsis)

When you think about cosmology and the fundamental questions scientists are trying to address, you inevitably wind up thinking about dark matter, dark energy and black holes as the three biggest topics that shape our view of the Universe.

Image credit: NASA/WMAP science team.

Image credit: NASA/WMAP science team.

But there are plenty of other aspects to this branch of science that deserve at least equal attention, including two important aspects that are rarely talked about with the same fervor or frequency: the highest energy particles in the Universe and the Universe’s “dark ages,” a period after the formation of neutral atoms but before any stars had formed!

Image credit: Pierre Auger Observatory, via

Image credit: Pierre Auger Observatory, via

Amanda Yoho has the full story; read and enjoy!


  1. #1 Albert de Koninck
    Brossard, Quebec, Canada
    November 26, 2014

    Please – not every reading this is American so please provide metric equivalents for distance, area, etc. Measurements. I am getting sick of having to do conversions every time I come across so – called customary measurements.

  2. #2 Monty
    November 29, 2014

    Wow! Why do you call God “Dark Matter”? It can’r be seen, it’s all powerful…

  3. #3 sr rajurkar
    madahya pradesh
    November 29, 2014

    how are star present in galaxies

  4. #4 Michael Kelsey
    SLAC National Accelerator Laboratory
    November 29, 2014

    @Monty #2: The difference we have observable, reproducible evidence for one, but not for the thousands of others.

  5. #5 Bill
    May 24, 2015

    When a computational cosmologist tells me that a wavelength of one meter equals a frequency of one gigahertz, and that that’s the frequency of FM radio stations, I start to worry. When they tell me they’re going to build a detector on “the dark side of the moon” I really worry. Didn’t anyone proofread this?

  6. #6 Wow
    May 24, 2015

    Should we worry that your post there seems to have been a complete and utter brain-melting non-sequitur?

    Or should we *really* worry?

  7. #7 PJ
    Perth, west Oz
    May 24, 2015

    Hmmm, 1 Ghz = 30 cm, 1/2 wave = 15 cm = ~ 6″ but no FM stations in this country – FM is 88 to 108 Mhz …….

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