Astronomy
esiegel | September 17, 2015“Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.” -Carl Sagan
And yet, we're not alone, in that the Universe has hundreds of billions of galaxies, each with hundreds of billions of stars in it, to keep us company. Thanks to the power of the world's most advanced telescopes like Hubble, we've been able…
esiegel | September 14, 2015“This then, I thought, as I looked round about me, is the representation of history. It requires a falsification of perspective. We, the survivors, see everything from above, see everything at once, and still we do not know how it was.” -W.G. Sebald
From their discovery in the 1600s, Saturn's rings have been a source of wonder and puzzlement to skywatchers everywhere. The only ring system visible through most telescopes from Earth, Saturn's main rings at more than 70,000 km long, yet no more than 1 km in thickness.
Image credit: NASA/JPL/Space Science Institute.
Once thought to have only…
esiegel | September 7, 2015“The thing is, when you see your old friends, you come face to face with yourself. I run into someone I’ve known for 40 or 50 years, and they’re old. And I suddenly realize I’m old. It comes as an enormous shock to me. ” -Polly Bergen
It isn't just humans that age rapidly, but stars as well. For the hottest, brightest stars, the aging process occurs the most quickly, as the most massive stars live only a few million years at most before going supernova. Such is the fate of the giant O-class star, ζ Ophiuchi, located just 370 light years away.
Image credit: E. Siegel, created with the free…
esiegel | August 31, 2015“It is marvelous indeed to watch on television the rings of Saturn close; and to speculate on what we may yet find at galaxy’s edge. But in the process, we have lost the human element; not to mention the high hope of those quaint days when flight would create ‘one world.’ Instead of one world, we have ‘star wars,’ and a future in which dumb dented human toys will drift mindlessly about the cosmos long after our small planet’s dead.” -Gore Vidal
And yet, it isn't just the rings of Saturn that fascinate us, nor can we simply "watch them on television," as Gore Vidal sadly declared. Every twenty…
esiegel | August 24, 2015“What is history? An echo of the past in the future; a reflex from the future on the past.” -Victor Hugo
When stars are born of a certain mass -- between about 10 and 40 times the mass of the Sun -- they can evolve into yellow supergiants when they burn through the hydrogen in their cores. As the outer layers expand, cool, contract, heat up, and pulse in this fashion, they can occasionally be blown off to form a gaseous cloud surrounding the star.
Image credit: ESA/Hubble & ESO.
These Cepheid variable stars have been known and studied for over a hundred years, and vary tremendously in…
esiegel | August 17, 2015“This method of viewing the heavens seems to throw them into a new kind of light. They are now seen to resemble a luxuriant garden, which contains the greatest variety of productions, in different flourishing beds; and one advantage we may reap from it is, that we can, as it were, extend the range of our experience to an immense duration.” -William Herschel
When a large molecular cloud of gas begins to collapse under its own gravity, whether spontaneously or triggered by a "nudge" in space, the runaway process leads to many new star clusters, which in turn lead to ionization, ultraviolet…
esiegel | August 12, 2015“Men of genius are often dull and inert in society; as the blazing meteor, when it descends to earth, is only a stone.” -Henry Wadsworth Longfellow
And yet, not all meteors nor all meteor showers are created equal. Some showers are duds, with the meteors being infrequent, inconsistent, short-lived and dim. Hardly worth mentioning. On the other hand, meteor showers can be spectacular, with frequent events, consistent displays year-to-year, lasting many consecutive nights and with bright, luminous fireballs.
Image credit: David Kingham 2013 | The National Maritime Museum.
The Perseids,…
esiegel | August 9, 2015“Studying whether there’s life on Mars or studying how the universe began, there’s something magical about pushing back the frontiers of knowledge. That’s something that is almost part of being human, and I’m certain that will continue.” -Sally Ride
When you travel some hundred-million kilometers through space to land, softly, on another world, you deserve a little bit of credit. The Mars Curiosity Rover has lived up to its hype and its expectations since its 2012 landing, and has responded with not only some remarkable science, but perhaps the best images of the Red Planet's surface ever…
esiegel | August 6, 2015“The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to -271.3°C, not much good for defrosting the pizza, let alone cooking it.” –Stephen Hawking
Imagine you traveled out into empty space. Away from any and all planets, stars, galaxies, and matter in general: normal or dark. Would you simply find yourself immersed in an empty, energy-free abyss? Not so! You'd still be bathed in radiation: not just from distant starlight, but from the afterglow of the Big Bang itself.
Image credit: ESA and the Planck…
esiegel | August 5, 2015“We are not the same persons this year as last; nor are those we love. It is a happy chance if we, changing, continue to love a changed person.” -W. Somerset Maugham
This past Monday (thanks, PJ), I celebrated the completion of my 37th orbit around the Sun. This is something we all have the opportunity to do once a year, and we can choose to reflect on how we've changed and what we'd like to change further in the year ahead. On the grandest scales, though, the Universe might seem like it hardly cares at all about another years that's passed.
Image credit: J. NASA and Jeff Hester (Arizona…
esiegel | August 3, 2015“That, then, is loveliness, we said,
Children in wonder watching the stars,
Is the aim and the end.
Being but men, we walked into the trees.” -Dylan Thomas
Yet when you look at the night sky, it isn't watching the stars that reveals all of the Universe's secrets, nor by looking with what you can see with your eyes. Looking beyond what visible light can teach us often reveals a whole Universe of wonder that we'd never see otherwise.
Image credit: NASA/JPL-Caltech/WISE Team.
Looking in infrared light, NASA's Wide-field Infrared Survey Explorer (WISE) reveals the intricate structure behind…
esiegel | August 1, 2015“It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn’t feel like a giant. I felt very, very small.” -Neil Armstrong
This past week saw a whole lot of interesting things happen, including tonight's second full moon of the month: a rare blue moon. In my life, I saw the International Space Station for the first time, but here at Starts With A Bang, there was so much to learn about and share, including:
When will the stars go dark? (for Ask Ethan),
Advertising vs. art (for our Weekend…
esiegel | July 30, 2015“To be is to be the value of a variable.” –Willard Van Orman Quine
Those constant, fixed points of light in the night sky -- the stars -- turn out not to be so constant if you looked with great precision at them. A star like our Sun varies in brightness, periodically, by about 0.1% over the span of a few years, but many stars vary by 99% or more from brightest to dimmest.
Image credit: British Astronomical Association Variable Star Section, via http://www.britastro.org/vss/.
For centuries, we knew of only a handful of these objects, yet now they're known to be commonplace. What causes this…
esiegel | July 28, 2015When you close your eyes and picture a galaxy, what pops into your mind? For most people, it's a beautiful, spiral shape, where a bright central region fans out with arms that wind around and around, over and over, littered with brilliant, glittering stars. And in almost all the pictures you see, there are two main arms making this up, with perhaps additional "spurs" shooting off of the primary arms.
Image Credit: NASA/JPL-Caltech/ESO/R. Hurt.
But is this really representative of what galaxies look like? Or is it just that these are the images of galaxies that stand out most for us?…
esiegel | July 27, 2015“Our knowledge of stars and interstellar matter must be based primarily on the electromagnetic radiation which reaches us. Nature has thoughtfully provided us with a universe in which radiant energy of almost all wave lengths travels in straight lines over enormous distances with usually rather negligible absorption.” -Lyman Spitzer, Jr.
There's nothing quite like looking at a galaxy, all aglow with the light from billions upon billions of stars shining at once. Some reaches our eyes, some is obscured by light-blocking dust, and all of it comes together to give a spectacular sight.
Image…
esiegel | July 23, 2015“You can spend too much time wondering which of identical twins is the more alike.” -Robert Brault
Earlier today, NASA announced the "most Earth-like exoplanet yet," a planet just 60% larger in radius than our own, orbiting a star of the same spectral class as our Sun and with an almost identical orbital period: 385 days.
Image credit: NASA/JPL-CalTech/R. Hurt.
But is this really the most Earth-like planet we've discovered? It's significantly larger and five times as massive, and may actually be more like Neptune than like Earth. In fact, other properties may be much more important if we…
esiegel | July 21, 2015When you think of the night sky -- of a good, dark night sky -- you probably think of going away, far into the wilderness, away from all human activity. If you're a little more clever, you'll head up, to the top of a high mountain, where the air is thin and steady.
Image credit: Mike Prokosch.
And if you live in a country like Chile, that has the high altitude of the Andes mountains that overlooks the still air of the South American Pacific, that's exactly what you're in for. Luckily, Starts With A Bang writer (and theoretical astrophysics professor) Brian Koberlein recently took a trip…
esiegel | July 20, 2015“Deep into that darkness peering, long I stood there, wondering, fearing, doubting, dreaming dreams no mortal ever dared to dream before.” -Edgar Allan Poe
Thanks to the Hubble Space Telescope, we've learned for a certainty that the black abyss of empty space isn't really so empty. Far beyond what we can perceive with our naked eye (or even ground-based telescopes), galaxies exist and go on for tens of billions of light years.
Image credit: Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, and UKSTU/AAO, via http://hubblesite.org/newscenter/archive/releases/2010/01/image/h/.
So what…
esiegel | July 16, 2015“Man loves company — even if it is only that of a small burning candle.” -Georg C. Lichtenberg
The Sun, like all stars initially, burns hydrogen fuel into helium through the process of nuclear fusion. But as the Sun ages, as do all stars over a certain mass, it starts burning those heavier elements in its core, going through different phases of its life cycle and eventually ending in a planetary nebula/white dwarf combination.
Image credit: NASA, W. Sparks (STScI) and R. Sahai (JPL).
But are these transitions sharp or gradual, and what of even more massive stars that start burning carbon,…
esiegel | July 14, 2015“Words are the source of misunderstandings.” -Antoine de Saint-Exupéry
Back in 2006, the International Astronomical Union officially defined the word "planet" for the first time, claiming that as long as something met all three of the following criteria:
It was in hydrostatic equilibrium (pulled itself into a spherical/spheroidal shape under its own gravity),
It didn't orbit any other body larger than itself (i.e., wasn't a moon), and
Cleared its orbital path of all other major bodies,
then it got to be a planet.
Image credit: © 2015 The Johns Hopkins University Applied Physics Laboratory…