Astronomy
esiegel | July 13, 2015“Life is a mirror and will reflect back to the thinker what he thinks into it.” -Ernest Holmes
When you've got a gas cloud in space that emits light, it's only for one of two reasons:
Either it's at high enough temperatures that its atoms are excited and it's emitting its own light as the electrons fall in energy and recombine with nuclei,
Or it's cool and neutral, and is reflecting light off of the brightest stars in its vicinity.
That latter case has a dead giveaway: it always shines blue.
Image credit: ESO/Igor Chekalin, via http://www.eso.org/public/images/eso1105a/.
But there's much…
esiegel | July 9, 2015“Don’t go around saying the world owes you a living. The world owes you nothing. It was here first.” –Mark Twain
You probably think you know the eight planets pretty well, don't you? Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, in order, with the four rocky inner worlds circumscribed by the four gas giants. But can you identify which is which?
Image credit: NASA / Lunar and Planetary Laboratory.
It isn't so easy if you're just shown a picture of a portion of a world, though, or a few candidate images that look somewhat similar, but only one is of the world you want.…
esiegel | July 8, 2015“Put two ships in the open sea, without wind or tide, and, at last, they will come together. Throw two planets into space, and they will fall one on the other. Place two enemies in the midst of a crowd, and they will inevitably meet; it is a fatality, a question of time; that is all.” -Jules Verne
There are plenty of questions one can ask about our local neck-of-the-woods here. As it stands, the more we learn and discover, the more we realize there is to learn and be discovered. On Monday, xkcd asked some of the most compelling and puzzling questions there are to ask about our very own Solar…
jdupuis | July 7, 2015Science! What's it good for? Working towards better knowledge about the natural world!
Under review today are two books that approach what science is and what it's good for from very different angles. Steven Weinberg is a Nobel laureate in physics and in his book To Explain the World: The Discovery of Modern Science he uses the example of the development of physics and astronomy in modern times to show how the scientific method has been developed and evolved over time. Harry Collins is a sociologist who was instrumental in developing the fields of science studies and the sociology of…
esiegel | June 29, 2015“Now, Venus is an extremely hostile environment, and as such presents a lot of challenges for a science fiction author who wants to create life there. However, as I began to research it more thoroughly, I found myself intrigued by the possibilities the world offers.” -Sarah Zettel
Of all the worlds in our Solar System, Venus is perhaps the most like Earth. It's the closest to us in size, in mass, in orbit, and in elemental content. The biggest difference, of course, is Venus' atmosphere.
Image credit: ESA/MPS, Katlenburg-Lindau, Germany / Venus Express.
Over 90 times as thick as Earth's…
esiegel | June 24, 2015“For my part I know nothing with any certainty, but the sight of the stars makes me dream.” -Vincent Van Gogh
When we look out into the Universe, farther back to greater distances, we're also looking back in time, farther and farther into the past. If we could look back far enough, close enough to the Big Bang, we'd be able to see the very first stars ever formed in the Universe: stars formed from the Big Bang's leftover material itself.
Image credit: European Southern Observatory (ESO).
We'd never been able to find these before, but by looking at a starburst galaxy at extremely high…
esiegel | June 22, 2015“Hundreds or thousands of years from now, when people look back at our generation, they will remember us for being the first people who found the Earth-like worlds.” -Sara Seager
Just a scant 25 years ago, we had never yet found and confirmed another planet orbiting a star other than our own. Fast forward to the present, and we've not only got thousands, we've found a significant number of rocky planets at the right distance from stars even longer-lived than our Sun for liquid water to suggest that there are literally billions of potentially habitable worlds in our own galaxy.
Image credit:…
esiegel | June 21, 2015“The progress of science is strewn, like an ancient desert trail, with the bleached skeleton of discarded theories which once seemed to possess eternal life.” -Arthur Koestler
For every galaxy out there, what we typically see -- the stars -- is only representative of a tiny fraction, maybe 2%, of all the mass that's present within. For everything else, there's dark matter, planets, gas, dust, molecular clouds and more.
Image credit: Dobbs et al. (simulation snapshot) of the Milky Way’s “bones,” via http://milkywaybones.org/media-gallery/detail/13836/54371.
But while other galaxies tended…
esiegel | June 17, 2015“Scientific ideas should be simple, explanatory, predictive. The inflationary multiverse as currently understood appears to have none of those properties.” -Paul Steinhardt, 2014
Cosmic inflation is alternately talked about by serious scientists as either the definitive beginning to our Universe, the thing that happened before and set up the Big Bang with absolute certainty, or a speculative fiction that can never be falsified, leading to nothing but untestable predictions and things that only mattered after-the-fact of their discovery.
Image credit: Bock et al. (2006, astro-ph/0604101);…
esiegel | June 14, 2015“People get cranky when you burst their bubble. Over time, advances in astronomy have relentlessly reinforced the utter insignificance of Earth on a celestial scale.” -Nathan Myhrvold
When new stars form from a collapsing molecular cloud, the hottest, bluest, brightest stars emit high-energy ultraviolet radiation. This evaporates, ionizes and pushes the gas outwards, creating a bubble effect.
Image credit: Copyright 2006 Brad Moore and Southern Astro, via http://hubblesite.org/newscenter/archive/releases/2008/34/image/e/.
Thanks to the Hubble Space Telescope and its ability to hone in…
esiegel | June 7, 2015“The wonder is, not that the field of the stars is so vast, but that man has measured it.” -Anatole France
Wherever large, dense collections of cool gas gather together under the force of their own gravity, new stars are bound to form. Every galaxy goes through peaks and lulls in star formation, yet at any given time, one star cluster will always be the largest and most massive.
Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team.
Discovered only in the 1960s due to its location in the galactic plane, Westerlund 2 holds…
esiegel | June 3, 2015“Movin’ right along.
You take it, you know best.
Hey, I’ve never seen the Sun come up in the West?” -The Muppet Movie
Few things in this world are as regular as sunrise and sunset. With the application of a little physics, you can predict exactly where and when the sun will rise or set from any location on Earth. Thus far, every world in our Solar System -- planet, moon and asteroid -- has had the exact same experience as us.
Image credit: NASA Ames / Dana Berry, of the LADEE spacecraft.
But out in the Kuiper belt, Pluto is different. The only known world in the Solar System where a…
esiegel | June 1, 2015“Lost — yesterday, somewhere between sunrise and sunset, two golden hours, each set with sixty diamond minutes. No reward is offered, for they are gone forever.” -Horace Mann
The beauty of a sunset (or sunrise) is rare and unique, happening but once a day for those of us on Earth. But aboard a spacecraft like the ISS, these are sights that happen sixteen times a day.
Image credit: NASA / Karen Nyberg / ISS Expedition 36/37.
And while we're used to dramatic, slow sunsets where it takes between two and three minutes simply for the Sun's disk to drop below the horizon, it takes mere seconds…
esiegel | May 24, 2015“The world exploded into billions of atoms, and when it rearranged itself, it may have looked the same, but really, it was a Whole New World.” -Claire LaZebnik
At the center of almost every galaxy is a supermassive black hole (SMBH); at the center of almost every cluster is a supermassive galaxy with some of the largest SMBHs in the Universe. And every once in a while, a galactocentric black hole will become active, emitting tremendous amounts of radiation out into the Universe as it devours matter.
Image credit: NASA/CXC/Ohio U./B.McNamara, via http://chandra.harvard.edu/photo/2005/ms0735/…
esiegel | May 21, 2015“The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown.” -H. P. Lovecraft
When it comes to risk assessment, there's one type that humans are notoriously bad at: the very low-frequency but high-consequence risks and rewards. It's why so many of us are so eager to play the lottery, and simultaneously why we're catastrophically afraid of ebola and plane crashes, when we're far more likely to die from something mundane, like getting hit by a truck. One of the examples where science and this type of fear-based fallacy intersect is the…
esiegel | May 19, 2015“One of the dreariest spots on life’s road is the point of conviction that nothing will ever again happen to you.” -Faith Baldwin
Bet you thought you knew it all about the asteroid belt. These frozen, ice-and-rock worlds orbit farther out from Mars, closer in than Jupiter, and occasionally get hurled towards the inner Solar System by gravitational interactions. But the largest world, Ceres, at just about half the diameter of the Moon (or the size of Texas), exhibits an unusual surprise: a brilliant set of white spots at the bottom of one of its largest craters.
Image credit: NASA/JPL-Caltech…
esiegel | May 18, 2015“Without any doubt, the regularity which astronomy shows us in the movements of the comets takes place in all phenomena. The trajectory of a simple molecule of air or vapour is regulated in a manner as certain as that of the planetary orbits; the only difference between them is that which is contributed by our ignorance. Probability is relative in part to this ignorance, and in part to our knowledge.” -Pierre-Simon Laplace
Originating from well out beyond the planets we're accustomed to, the cold, icy worlds of the outer Solar System normally roam in isolation, hardly noticed by anything at…
esiegel | May 11, 2015“And no one showed us to the land
And no one knows the where’s or why’s
But something stirs and something tries
And starts to climb towards the light” -Pink Floyd, Echoes
It's pretty difficult to imagine, but a little over 300 years ago, a supernova -- a dying, ultramassive star -- exploded, giving rise to such a luminous explosion that it might have shone as bright as our entire galaxy.
And nobody on Earth saw it.
Image credit: NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: R. Fesen (Dartmouth) and J. Morse (Univ. of Colorado).
Located in the plane of our Milky Way galaxy…
esiegel | May 7, 2015“Energy is liberated matter, matter is energy waiting to happen.” -Bill Bryson
When it comes to the Universe, you might think that energy really is only limited by rarity: get enough particles accelerated by enough supermassive, super-energetic sources, and it's only a matter of time (and flux) before you get one that reaches any arbitrary energy threshold. After all, we've got no shortage of, say, supermassive black holes at the hearts of active galaxies.
Image credit: NASA, ESA, Hubble Heritage (STScI/AURA).
And yes, we do find cosmic rays hundreds, thousands or even millions of times…
esiegel | May 5, 2015“No distance of place or lapse of time can lessen the friendship of those who are thoroughly persuaded of each other’s worth.” -Robert Southey
You might think that, when it comes to finding the most distant objects in the Universe, all we need is a good telescope, to leave the shutter open, and wait. As we accumulate more and more photons, we're bound to find the most distant, faint objects out there.
Image credit: NASA, ESA, R. Bouwens and G. Illingworth (UC, Santa Cruz).
It's a nice thought, but it misses an important fact: the Universe is expanding! And with that expansion, the…