radiation

Tag archives for radiation

Ask Ethan #16: What are Variable Stars?

“To be is to be the value of a variable.” -Willard Van Orman Quine It’s the end of the week once again, and the very end of our Year In Space 2014 Wall Calendar giveaway! So for this week’s Ask Ethan column, after dipping into our question/suggestion box, I’m very pleased to let Vera from…

What is the Big Bang all about?

“Twinkle, twinkle, quasi-star Biggest puzzle from afar How unlike the other ones Brighter than a billion suns Twinkle, twinkle, quasi-star How I wonder what you are.” -George Gamow The Big Bang is one of the greatest, revolutionary ideas in all of modern science, but it’s also one of the most successful ideas as far as…

How Big is Our Observable Universe?

“The mind, once expanded to the dimensions of larger ideas, never returns to its original size.” -Oliver Wendell Holmes When General Relativity supplanted Newton’s work as our theory of how gravity works in the Universe, it didn’t just change how we view how masses attract, it gave us a new understanding of what the questions where…

How can we see black holes?

“According to the special theory of relativity nothing can travel faster than light, so that if light cannot escape, nothing else can either. The result would be a black hole: a region of space-time from which it is not possible to escape to infinity.” -Stephen Hawking You may have encountered objects that are the same…

Big News about Black Holes!

This has been all over my inbox since the press release came out yesterday; it’s been on slashdot (thanks Brian), it’s been at space.com, and there’s a mediocre writeup on Universe Today. What’s the big news? Black Holes don’t destroy information after all! What is this whole information thing, anyway? Take a look at all…

Black Hole Kicked Out of Galaxy

No, not because it was too young to drink! Scientists at the Max Planck Institute for Extraterrestrial Physics were looking at some X-ray objects, and discovered something really weird: a very bright X-ray source moving out of a galaxy at nearly 3,000 kilometers/second! This thing is a goner. If our Sun were moving at even…

So, what’s the deal with this one? startswithabang.com reader Scott Stuart asks the following question: I was reading “The First Three Minutes” last night and came across an interesting section about blackbody radiation and energy density. The author states that as the universe expands, the number of photons running around (in the CMB, for example)…

startswithabang.com reader Andy has a great follow-up to his question on the Age & Size of the Universe, and asks: why does the CBR “appear” to come from a light sphere that “appears” NOW to be larger than the universe WAS when it first set off in a straight line on its 13.4 billion year…

The Universe isn’t a static place. Although the laws of nature (physics, chemistry, biology, etc.) don’t appear to change over time, everything in the Universe appears to evolve, and changes over time. One of the simplest ways that this happens is through Hubble expansion. General relativity tells us how the Universe expands, and more specifically,…

Faster-than-light travel: is it possible?

Apparently, this is becoming a good place for people to get their questions answered! My friend Brian, recently wanted to know what the possibilities were for faster-than-light travel. Specifically, he was interested in it because he wants humans to do it. Brian: but otherwise how will we ever have a civilization like that in Star…