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esiegel | October 11, 2014“Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever and to whatever abysses nature leads, or you shall learn nothing.” -T.H. Huxley
It's said that nothing lasts forever, and as far as we can tell, this is true. Every living thing that has ever lived will die; every star that's ever burned fuel will run out of it; galaxies will eventually be destroyed as their stars are thrown out from gravitational interaction, and even black holes will eventually decay.
Illustration credit: ESA, retrieved via http://chandra.harvard.edu/resources/…
esiegel | October 3, 2014“A single day is enough to make us a little larger or, another time, a little smaller.” -Paul Klee
As the time passes for us all, and we age, so too does everything else in the Universe. For an object like a black hole, it has the potential to form, grow or shrink as we move forward.
Image credit: Mark Garlick (University of Warwick).
The question, of course, that we might ask is how, and by how much? Is normal (baryonic) matter the only culprit, or can dark matter make a difference for this as well? And if so, under what circumstances, and can it teach us anything about dark matter in the…
esiegel | September 26, 2014“I sometimes catch myself looking up at the Moon, remembering the changes of fortune in our long voyage, thinking of the thousands of people who worked to bring the three of us home. I look up at the moon and wonder, when will we be going back, and who will that be?” -Tom Hanks
Imagine, hopefully, the not-too-distant future, when humanity launches the first manned mission to another planet in our Solar System: probably Mars. You're on your way, and then -- all of a sudden -- you realize that something is wrong.
Image credit: Frank G., via https://shufti.wordpress.com/2011/11/26/aaa-around-…
esiegel | September 19, 2014“From earliest times, humans — explorers and thinkers — have wanted to figure out the shape of their world. Forever, the way we’ve done that is through storytelling. It is difficult to let the truth get in the way of a good story.” -Adam Savage
When we look back into the Universe, there's a wonderful, remarkable story that it tells us about itself. The more light we gather, of different wavelengths and over longer periods of time, the more we can discover.
Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and…
esiegel | September 5, 2014“Why do people have to be this lonely? What’s the point of it all? Millions of people in this world, all of them yearning, looking to others to satisfy them, yet isolating themselves. Why? Was the earth put here just to nourish human loneliness?” -Haruki Murakami
Of all the ways our Universe can end -- recollapsing into a firey singularity, freezing out into a cold, icy void -- perhaps the scariest conceivable fate is one where galaxies are ripped apart, stripped of their stars, where planets come undone, molecules and atoms are torn away from one another and, at last, spacetime itself is…
esiegel | August 29, 2014“After all the ‘Universe’ is a hypothesis, like the atom, & must be allowed the freedom to have properties & to do things which would be contradictory & impossible for a finite material structure.” -Willem de Sitter
Dark energy was one of the biggest surprises to come along in the past generation, from a scientific standpoint. It's only intuitive to think that the Universe -- with gravity fighting the initial expansion ever since the Big Bang -- and all the galaxies in it would continue to slow down over time. But with a significant positive amount of energy inherent to space…
esiegel | August 15, 2014“Es ist immer angenehm, über strenge Lösungen einfacher Form zu verfügen.” (It is always pleasant to have exact solutions in simple form at your disposal.) -Karl Schwarzschild
The Universe is a vast and complex place, full of a diversity of structure from the smallest scales to the largest. And yet, by many accounts, it's a wonder that it came to be this way at all.
Image credit: NASA, retrieved from Pearson Education / Addison Wesley.
If things were just a little bit different at the very beginning, the Universe could have recollapsed in on itself in a mere fraction-of-a-second after the…
esiegel | August 9, 2014“Whenever you have infinities in a theory, that’s where the theory fails as a description of nature. And if space was born in the Big Bang, yet is infinite now, we are forced to believe that it’s instantaneously, infinitely big. It seems absurd.” -Janna Levin
Of course, we don't believe space was born in the Big Bang, but this wasn't intuitive for a long time! Indeed, given the cosmic unknowns of inflation, dark matter and dark energy, and the fact that what we consider to be "normal matter" only makes up around 5% of the total amount of energy in the cosmos, isn't it time to revisit the Big…
esiegel | August 1, 2014“In my better sense of mind, I know that I’m far from alone and far from the worst, and the earth keeps spinning. Everything keeps moving, with or without me.” -Phil Anselmo
The Universe is a chaotic place, where nothing truly exists in isolation. Even if, at the moment of the Big Bang, nothing in the Universe was born having had any interactions with anything else, that state wouldn't have lasted for long.
Image credit: ESA and the Planck Collaboration.
Even the most pristine "baby picture" of the Universe we have comes only after astronomical numbers of interactions for each and every…
esiegel | July 26, 2014“Ignorance is hardly unusual, Miss Davar. The longer I live, the more I come to realize that it is the natural state of the human mind. There are many who will strive to defend its sanctity and then expect you to be impressed with their efforts.” -Brandon Sanderson
At the risk of inflaming everyone who doesn't think exactly like I do -- which is quite likely to literally be everyone who reads this -- sometimes I get a submission for Ask Ethan that I think is far too important to not address. And this week's entry, from Jonathan Hasey, really resonated with me.
Image credit: Randall Munroe of…
esiegel | July 19, 2014“You can observe a lot by just watching.” -Yogi Berra
Sure, the quantum Universe is a little bit spooky. Things that we're used to being "determined" here in the macroscopic world, like where a particle will end up if you throw it, aren't so simple if we head on down to subatomic scales.
Image credit: user Ufonaut99 from network54's GSJ Physics Forum, original via http://universe-review.ca/.
While you might have often heard that things are only determined by observation, does that have anything to do with you, the observer? Or is that just an anthropomorphized way of talking about what…
esiegel | July 12, 2014“Think left and think right and think low and think high. Oh, the thinks you can think up if only you try!” -Dr. Seuss
For almost a year now, you've all been sending in your questions and suggestions to me, and I've been picking my favorite one of the week for Ask Ethan, our weekly Q&A series. This week, though, the question goes a little deeper than I'm used to taking on.
Image credit: Wikimedia Commons users Frédéric MICHEL and Azcolvin429, annotated by me.
Our observable Universe goes on for 46 billion light-years in all directions, but what's out there beyond what we can observe?…
esiegel | July 4, 2014“One has to be an optimist; one has to hope that somewhere there’ll be new measurements to be made and that they will open up new vistas for us theorists to play with.” -Jim Peebles
It was one of the most hotly contested questions for decades: we first expected and then found supermassive black holes at the centers of practically all large galaxies. But how did they get there?
Image credit: KIPAC / SLAC / Stanford, via http://kipac.stanford.edu/kipac/research/agn.
In particular, you could imagine it happening either way: either there was this top-down scenario, where large-scale structures…
esiegel | June 27, 2014“I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.” -Johannes Kepler, 1601
It's easy to think of some things as eternal, even though nothing truly is. The Sun is long lived, and it has another 7 billion years (or so) to go before it runs out of fuel, but eventually it, too, will die. But surely gravitational orbits will outlast us all, right?
Image credit: Petr Scheirich, 2005, via http://sajri.astronomy.cz/asteroidgroups/groups.htm.
As it turns out, even the simplest system you can set up -- of a single small mass orbiting a large…
esiegel | June 20, 2014“The brighter you are, the more you have to learn.” -Don Herold
There's a big difference between the Summer Sun and the Winter Sun, and I'm not talking about anything to do with the Sun itself.
Image credit: SOHO-EIT Consortium, ESA, NASA.
No, I'm talking about what you feel here on Earth due to the Sun's rays! There's no doubt that the Sun warms the Earth, and that it warms your portion of the Earth very differently during the Summer months as opposed to the Winter months. But did you ever stop to consider why? Is it the Sun's fault? Our orbit's fault? Something else?
Image credit: Larry…
esiegel | June 14, 2014“Sometimes a person has to go a very long distance out of his way to come back a short distance correctly.” -Edward Albee
Every week on Ask Ethan, we've been taking a look at my favorites of the questions you send in. And one of the things you've been wondering about is this: when we look at an object way out there in the Universe, how do we determine how far back in time we're looking.
Image credit: © 2013 Alan Dyer, via http://amazingsky.net/2013/12/10/orion-and-canis-major-rising/.
Is it as simple as measuring the distance to it and calculating the time by using the speed of light? If…
esiegel | June 6, 2014“If you are a dreamer come in
If you are a dreamer a wisher a liar
A hoper a pray-er a magic-bean-buyer
If youre a pretender com sit by my fire
For we have some flax golden tales to spin
Come in!
Come in!” -Shel Silverstein
There are fakers out there of all types, to be sure. But one of the most unexpected ones is the ultimate cosmic faker: a giant star that erupts and pretends to be a supernova!
Image credit: Celestia, by author / user HeNRyKus, with η Carinae at left and Canopus at right.
Just because something brightens tremendously to become visible to the eye, perhaps even outshining…
esiegel | May 30, 2014“They say the universe is expanding. That should help with the traffic.” -Steven Wright
When you think of the expanding Universe, you very likely think of galaxies moving away from one another, of space getting stretched, and quite possibly, of light redshifting as it travels through this expanding, stretching space.
Image credit: James Imamura of University of Oregon, via http://hendrix2.uoregon.edu/~imamura/123cs/lecture-5/lecture-5.html.
But does it have to be this way? In other words, these galaxies are moving away from us; are we sure that the light is getting redshifted because space…
esiegel | May 23, 2014“There is no greater agony than bearing an untold story inside you.” -Maya Angelou
From questions about the smallest scales to the largest, from Earthly phenomena to things we could only conceive of in theory, our Ask Ethan series is your opportunity to have anything you ask considered for a column. This week, though, is a little different than normal.
Image credit: Kenneth Libbrecht of http://www.its.caltech.edu/~atomic/snowcrystals/.
Rather than a question about science, I got a question about science writing. And in particular, what advice I'd give to a young scientist who was…
esiegel | May 16, 2014“There is no such thing as perpetual tranquillity of mind while we live here; because life itself is but motion, and can never be without desire, nor without fear, no more than without sense.” -Thomas Hobbes
Well, it finally happened: someone asked me about the accuracy (or inaccuracy) of a certain viral video.
And as you may have guessed, there's a little bit that's based in truth, but a whole lot more that's just out-and-out wrong. So what does the motion of our Solar System through the galaxy look like?
Image credit: National Astronomical Observatory ROZHEN, via http://sob.nao-rozhen.org…