Riddle Me This

In Astronomy by Brian Koberlein6 Comments

Anyone practicing science needs to get comfortable with uncertainty. Often the questions raised lead to an answer that is simply “we don’t know.” But there are times when we are instead faced with a contradiction. One set of evidence and theoretical reasoning leads to a conclusion in contradiction with another set of evidence. Usually these contradictions resolve themselves pretty quickly, but there are times when these contradictions grow into a paradox. While some of the most famous astronomical paradoxes are now used to demonstrate where our reasoning went wrong, others still challenge us with no clear resolution. 

What makes paradoxes so powerful is that they force us to reconsider both the evidence and our reasoning. If the Universe is self consistent (and we assume that it is) then there must be a solution to the paradox. So this week we’ll look at five major astronomical paradoxes. A couple have been solved, but most challenge even the most cutting edge research.

  1. To Infinity And Beyond – Olber’s paradox is perhaps the most famous example, but there are similar paradoxes involving gravity and thermodynamics. They all raise the same question: How can our Universe possibly be infinite?
  2. Cold Equations – When a white dwarf cools over time, can it actually get colder than absolute zero?
  3. Icy Sunrise – Our Sun was much cooler in its youth. So how is it that liquid water existed on a young Earth?
  4. Bigger Bang – There is an upper limit to the amount of energy a cosmic ray can have. So why do we observe cosmic rays that have even more energy than that limit?
  5. Over The Edge – The event horizon of a black hole is a point of no return. But if nothing can escape a black hole, isn’t the fundamental nature of physics violated?

We’ll start by confronting the assumption that even Einstein failed to challenge. In an infinite and ageless cosmos, how is it possible that the Universe is cold, dark and dominated by gravity? The paradox series starts next time.


  1. I agree with Arturo, this should be a terrific series of blog posts, each with – hopefully – lots of comments, questions, follow-ons, etc.

  2. Makes me think of renormalization/regularization in quantum physics. “This equation makes nonsensical predictions, but if we just ignore this HUGE term, it gives great predictions. Why? Uh, it’s a… a renormalization. Yeah, that’s what we’ll call it.” 😀

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