esiegel

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Ethan Siegel

Ethan was born in New York City as the son of a Jewish postal worker. He did his undergrad at Northwestern, taught public school in Houston, Texas and Los Angeles, California, before moving to Florida, where he got his PhD in theoretical astrophysics at the University of Florida. After that, he moved to Madison, Wisconsin, where he taught at the University of Wisconsin, ate too much cheese, and also met his life partner, Jamie. After working in astrophysics research at the University of Arizona and starting the world-renowned science blog, Starts With A Bang, he moved from the hellish desert to rain-soaked Portland in 2008. Since then, he's been a professor at the University of Portland and Lewis & Clark College, grown a nationally renowned beard and mustache, got invited to join a circus and probably drank more beer than a healthy person should. He currently works as the head curator at Trapit, and can't wait to tell you a little bit more about the Universe.

Posts by this author

Brightest thing ever?
Those of you who keep up with your news may have seen this headline on CNN last week: Star Explodes Halfway Across Universe. What they're talking about is a Gamma-Ray Burst, which was so bright that, despite being 7.5 billion light years (that's 2.3 Gpc) away, it was still visible on Earth with the…
Weekend Diversion: Jessie and Slater?
Remember the TV show Saved By The Bell? It was a high school comedy that was popular when I was in Junior High, and it was, of course, completely preposterous and cheesy. Like what you'd get if you married Beverly Hills: 90210 with Fast Times at Ridgemont High, and then cleaned it up to make it…
The Cosmic Background Radiation
This was the third and final piece of the puzzle that led to the acceptance of the Big Bang and the rejection of all alternatives: the discovery of the background radiation left over from the Big Bang. The "leading theory" before this was discovered was the Steady-State theory. Sure, they knew of…
The Abundance of Light Elements
This is the second key prediction of the Big Bang: the Universe was, before any stars formed, made up of about 75% Hydrogen and 25% Helium, and much less than 1% of all other elements combined. How does the Big Bang predict this, and how to we observe it? Well, remember we said the Universe was hot…
The Hubble Expansion of the Universe
This is the first of the key predictions of the Big Bang theory, that everything in the Universe will expand according to Hubble's Law, or that the speed that other galaxies recede from us is proportional to their distance from us. Let's jump into the details of why the Big Bang predicts it, and…
Did It All Start With A Bang?
Here's a really fundamental question, and yet one that I think that most people don't know the answer to: How do we know that the Big Bang is the right theory of the origin of the Universe? There are a bunch of alternative theories out there, after all, like Plasma Cosmology, the Steady-State…
Weekend Diversion: Rainbows!
Starts with a bang reader Zrinka asks us how rainbows work, and that's a great question for the weekend, since I'm driving up to Portland, OR right now. (The desert is lousy for rainbows when it doesn't rain!) So you've seen something like this before, although maybe yours isn't as famous as Galen…
Happy March 14th, or 3.14…
Happy Pi Day! Even the BBC has a nice article on this one. Maybe someday, the US will, too. And yes, it's nerdy, I know, but what's frightening is that I actually have the first line of that image memorized somehow...
Inflation’s Problems and Alternatives
This month's issue of Physics Today has an interesting article by Robert Brandenberger of McGill University, entitled Alternatives to Cosmological Inflation. As a refresher, cosmological inflation is the theory that sets up the Big Bang: it takes whatever was in the Universe prior to inflation and…
Say Goodbye to Virgo…
Aaah, the Virgo cluster. A huge cluster of hundreds of galaxies, and our closest large neighbor in the Universe. People have known for a long time that although Virgo is still redshifting away from us, it isn't quite as fast as we would expect from the Hubble expansion rate of the Universe. Does…
The Universe is Accelerating?
Sure, there's dark energy, but what does that really mean? First off, there's the bizarre phenomenon we see: very distant objects appear dimmer than we expect in a Universe filled with just matter and space. This supernova (above) should appear much brighter for how distant it is, based on what we…
Afraid of the Dark?
So I gave a public lecture last (Monday) night called, "Afraid of the Dark: How We Know What We Can't See" and videotaped it. Now, I'm pretty good at what I'm doing right now (research in theoretical cosmology), but I'm really good at public speaking and teaching, and here is me telling a public…
Water on Mars, Part II: Holden Crater
So in a recent column I told you all the problems with having water on Mars in recent history -- namely that the atmosphere is too thin to have supported it. But many of you have (rightly) pointed out to me that there is some evidence that there could have been water on Mars a very long time ago,…
Weekend Diversion: Video Editing = Musical Talent?
Sometimes I wonder if I'm going to need to learn video editing to make this outreach thing work. I might do well to follow the lead of this guy, who's a Norwegian named Lasse Gjertsen, and who's posted a video of him "playing drums and piano." Well, playing drums and piano kinda. But damn, I…
WMAP results: Cosmology from the CMB
The cosmic microwave background is the radiation left over from the big bang. It's very uniform, 2.725 Kelvin everywhere. We're moving with respect to it, so there's a doppler shift, and we see that as a dipole moment in the Temperature. When we subtract that out, we see variations on the order of…
Q & A: Where does Matter Come From?
I love The Straight Dope. For 35 years, people have written in and asked some of the most difficult-to-answer questions on any topic you can think of; the staffers, writing under the pseudonym Cecil Adams, do their best to get to the bottom of their questions. Well, they also have a message board,…
Was there Ever Liquid Water on Mars?
People love to speculate that Mars was once a great place for life to form, and claim that there is plenty of evidence that there used to be oceans and rivers there. But this isn't true. People used to claim there were big Canal-like features on Mars, and used this as evidence that Mars was very…
Mark your calendars: April 8th
Well, it's not technically a weekend diversion, but something awesome happened in the wake of my recent Awards-show posting of the Carnival of Space. David Livingston, a blogger over at Space Cynics and a radio host of The Space Show, has invited me to be his guest on his April 8th broadcast of his…
Bring him to me!
The Milky Way galaxy is a relatively big spiral galaxy. So is Andromeda. There are about 20 dwarf galaxies that are gravitationally bound to us; combined with us, all of this makes up the local group. But Andromeda is moving towards us, and eventually, it's going to merge with us. I'll once again…
Carnival of Space #43: Oscar Edition
It's been a spectacular week for the film space industry, and here at Starts With A Bang!, we've got the recap of all the highlights that you may have missed while watching the countless Oscar montages. Take your time browsing and enjoying this site, and maybe even find out what the question is if…
How old is the Sun in Galactic years?
The Moon goes around the Earth, the Earth goes around the Sun, and the Sun goes around the center of the Milky Way. We know the Moon takes about 4 weeks to make its trip around the Earth, and that causes the Moon phases: We also know that the Earth takes one year to go around the Sun, and that…
How did Life on Earth Originate?
I was thinking about the timeline that brought us here, today, from the origin of the Universe up through the present day. I realized that the most uncertain thing that we know of, the step that we have the least information about, is the origin of life on Earth. All hypotheses about how life on…
Q & A: Why is the Microwave Background so Uniform?
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 trip…
Q & A: What is Energy?
Let me set the scene for you: I'm fresh off my Ph.D., teaching introductory physics at the University of Wisconsin. I'm trying to demonstrate how to turn potential energy into kinetic energy, and so I ask this simple question: What is Energy? And I get a stunned silence back from the room. One of…
Weekend Diversion: Mmmmmm… MEAT!
As someone who's spent a lot of time in a University setting, one of the thing that often shocks me is the number of vegans that are out there. Why is it shocking? Because you need meat for proper nutrition. Now, I thought this was common knowledge, that humans are omnivores and that eating other…
Q & A: The Age and Size of the Universe?
Alright; this is a question I've been putting off for various poor reasons, but Starts With A Bang! reader Andy asks: If Im looking at something, the light from which has taken 15 billion years to get to me, and there was only an opaque ball of radiation and stuff 15 billion years ago, why do I see…
Lunar Eclipse: Clouded out here!
I was driving home from work at about 6:30 today and noticed the Moon, still orange, hanging low on the horizon. The lower left corner was just starting to be shadowed by the Earth. As it rose a little higher, it turned yellow and then white, as we learned it should. Then we got clouded out, and…
Pulsars, Dark Matter, and the Size of our Galaxy
Alright, startswithabang-ers, Ben, my most avid commenter, saw me online while I was eating breakfast this morning, and pointed me to this new press release. Now, before you get started clicking on everything, the guy who the release is about is Brian Gaensler, who's a really nice guy, lives in…
Q & A: Can We Clone a Woolly Mammoth?
What? Is this a joke, Ethan? Have you been watching Jurassic Park again, drinking Dino DNA or something? No, I got an interesting question from startswithabang.com reader and ichthyophobe Lucas: Over the years a few intact, frozen woolly mammoth have been found and procured by different scientists…
Why we need Dark Matter in the Universe.
Last week, Pamela Gay over at Star Stryder pointed me to a press release which claimed that, among other things, perhaps dark matter wasn't necessary. So I wrote a guest post on her blog explaining why it was. Apparently, some people still aren't convinced. So I will lay out for you all the reasons…