Stars
esiegel | January 12, 2012"Nothing leads the scientist so astray as a premature truth." -Jean Rostand
One of the most awesome events, literally, that happens in this Universe is when stars -- giant nuclear furnaces like our Sun -- die in the most energetic way possible: a supernova.
Video credit: Max-Planck-Institut für Astronomie (Ors Hunor Detre, Oliver Krause), via YouTube.
Every star that ever lived gets two chances to end their lives in this most spectacular of fashions. The hottest, bluest, most massive stars that are born burn through their nuclear fuel incredibly rapidly, accumulating a core of heavy metals…
esiegel | January 4, 2012"At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed." -Edwin Hubble
Given the relative peace of our night skies, combined with the vast distances from our Solar System to the nearest star, we don't often think about the cosmic catastrophes that took place in our past. But these catastrophes are the very things that gave rise to our Solar System in the first place!
Image credit: NASA, ESA and the Hubble Heritage (…
esiegel | January 3, 2012"Change, like sunshine, can be a friend or a foe, a blessing or a curse, a dawn or a dusk." -William Arthur Ward
Few things are as essential to our world as we know it as the primary source of our light, heat, and all the life that flourishes on Earth as the Sun itself.
Image credit: NASA / ESA / SOHO-EIT Consortium, retrieved from legacy.spitzer.caltech.edu.
And yet, there are two things that may strike you as very important when it comes to our Sun. One may be the fact that, at 150 million kilometers (93 million miles) distant, the Sun is so much closer to us than even the next closest…
esiegel | December 5, 2011"Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements, and it is an everyday reality throughout the Milky Way Galaxy." -Carl Sagan
(This post is coauthored by Dr. Peter Thieberger, Senior Physicist at Brookhaven National Laboratory.)
A cheap, clean, efficient and virtually limitless source of energy would be just what our world needs right about now. The cheap sources -- coal, oil, and gas -- are dirty, destructive, and limited, while the clean sources -- wind and solar -- are expensive and…
esiegel | November 28, 2011"One touch of nature makes the whole world kin." -William Shakespeare
In January of 2006, the Hubble Space Telescope -- equipped with the greatest telescope camera ever designed -- took this detailed picture of globular cluster NGC 1846.
Image credit: NASA and the Hubble Heritage Team, STScI/AURA, and P. Goudfrooij.
Like most globular clusters, this is a very tight, dense collection of perhaps a few hundred thousand stars, contained in a roughly spherical region just a few light years in size. Unlike most of the globular clusters we know, this one is not located within our own galaxy, but…
esiegel | November 2, 2011"The pages are still blank, but there is a miraculous feeling of the words being there, written in invisible ink and clamoring to become visible." -Vladimir Nabokov
The wonderful images we take of deep space -- from distant galaxies to all the stars, clusters, and nebulae within our own galaxy -- all have something in common.
Image credit: Wolfgang Brandner, Eva K. Grebel, You-Hua Chu, and NASA.
Light! More specifically, electromagnetic radiation. While this light isn't always in the visible portion of the spectrum, that's certainly the type of radiation we're most accustomed to. And that's…
esiegel | September 19, 2011"After all, the universe required ten billion years of evolution before life was even possible; the evolution of the stars and the evolving of new chemical elements in the nuclear furnaces of the stars were indispensable prerequisites for the generation of life." -John Polkinghorne
There are close to a whopping 1028 atoms in your body. And while just over half of them are hydrogen atoms, all the rest of them -- from Lithium to Uranium -- were made inside of stars, and ejected back out into the Universe, where, billions of years later, they made you.
Image credit: Ed Uthman.
In fact, a great…
esiegel | September 16, 2011Daughter, age 7: "Daddy, will the Earth always go around the Sun forever?"
Louis CK: "Well no, at some point the Sun is going to explode."
Daughter: (starts crying)
Louis CK: "Oh honey, this is not going to happen until you and everyone you know has been dead for a very long time."
Daughter: (continues crying)
As you all know, the closest supernova to us in the last quarter-century has recently gone off, currently shining in the faint, but relatively close Pinwheel Galaxy. (And starting tonight, early in the night, those of you with telescopes should go look for it!)
Image credit: Retrieved…
esiegel | September 14, 2011"We especially need imagination in science. It is not all mathematics, nor all logic, but is somewhat beauty and poetry." -Maria Mitchell
When you look up at the vastness of the night sky, if you've got few clouds, no Moon and sufficient darkness, you won't merely see thousands of tiny white pinpricks illuminating the black canopy of night.
Image credit: Flickr user kronerda.
Although, on average, stars are white in color, there's a very important reason for that. Our eyes have evolved to see a very narrow set of wavelengths of light, which we know as the visible light spectrum, ranging…
esiegel | August 20, 2011"An appeaser is one who feeds a crocodile, hoping it will eat him last."
-Winston Churchill
Ever wonder what will happen to the Earth once the Sun dies? Although it's happening very slowly, the Sun is burning through the nuclear fuel that powers it, giving off a tremendous amount of energy all the time as it happens.
Image credit: NASA's STEREO A spacecraft.
Like all stars, the Sun burns progressively hotter as it ages. A few billion years ago, solar output was 10% less than it is today, and a few billion years from now, it will burn so hot that our oceans will boil, something that only…
esiegel | August 12, 2011"...it is reasonable to hope that in the not too distant future we shall be competent to understand so simple a thing as a star." -Arthur Eddington, 1926
(For Mike H., who wanted to know.)
The Sun -- like nearly all stars -- burns bright through its nuclear reactions, sending light, heat and energy out into the Universe over a timespan of billions of years.
Image credit: NASA / ISS / Space Shuttle Atlantis.
But it didn't need to be that way. With the mass of about 300,000 Earths, nearly all of it in the form of hydrogen fuel, you can just as easily imagine a huge nuclear explosion on the…
esiegel | August 5, 2011"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." -Max Planck
(For Alan L., from the comments on this post.)
When you look out at the night sky, with the deepest, sharpest eyes possible, what is it that you see?
Image credit: NASA, ESA, R. Windhorst, S. Cohen, M. Mechtley, M. Rutkowski, R. O'Connell, P. McCarthy, N. Hathi, R. Ryan, H. Yan, and A. Koekemoer.
Galaxies! Lit by hundreds of billions of suns each (and that's just on average),…
esiegel | August 2, 2011"A birthday is just the first day of another 365-day journey around the sun. Enjoy the trip." -Author Unknown
Each of us has a birthday; mine is tomorrow, August 3rd. And while we're mucking around here on the ground, the Earth relentlessly orbits the Sun.
And while a sidereal year, or the time it takes the Earth to return to its same position in space, is not quite identical to a calendar year, it's awfully close. So much so, in fact, that with the exceptions of the planets having wandered a bit from year-to-year, you get the same night sky each and every year on your birthday.
Image…
esiegel | July 28, 2011"To correct a natural indifference I was placed half-way between misery and the sun. Misery kept me from believing that all was well under the sun, and the sun taught me that history wasn't everything." -Albert Camus
Our Sun has been shining brightly for over four billion years now, giving light, heat, and energy to our entire Solar System. But -- like every other star -- it won't continue to burn forever. In an estimated five-to-seven billion years, the Sun will cease its nuclear fusion reactions, and eventually contract down into a white dwarf star, losing a good fraction of its mass and…
esiegel | June 8, 2011"This nebula had such a resemblance to a comet in its form and brightness that I endeavored to find others, so that astronomers would not confuse these same nebulae with comets just beginning to shine." -Charles Messier
Astronomers have been scouring the skies for new discoveries since long before the invention of the telescope. Why, just with the naked eye and some dark skies, anyone can discover about 6,000 stars, five major planets, the Milky Way, and the occasional very faint nebula.
Image credit: Miloslav Druckmuller.
And of course, if you're very fortunate and very diligent, you could…
esiegel | May 25, 2011"We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special." -Stephen Hawking
You're probably familiar with the standard picture of our Universe. You've heard it all before: that the Universe we know of -- stars, planets, atoms, etc. -- is less than 5% of the Universe's total energy. That most of the matter is dark matter, and that most of the energy in the Universe isn't matter at all, but dark energy.
But recently, we've started to discover a couple of interesting things about the atoms in the…
esiegel | April 18, 2011"The lessons of science should be experimental also. The sight of a planet through a telescope is worth all the course on astronomy; the shock of the electric spark in the elbow outvalues all theories; the taste of the nitrous oxide, the firing of an artificial volcano, are better than volumes of chemistry." -Ralph Waldo Emerson
As a theorist, one of the challenges I face is bringing the experimental and observational sides of what we study to all of you. I understand its importance, its significance, and how it is the ultimate arbiter of our understanding. And yet, it is not my strongest…
esiegel | March 28, 2011"If it were worth the while to settle in those parts near to the Pleiades or the Hyades, to Aldebaran or Altair, then I was really there, or at an equal remoteness from the life which I had left behind, dwindled and twinkling with as fine a ray to my nearest neighbor, and to be seen only in moonless nights by him." -Henry David Thoreau
Two weeks ago, I asked if you knew your brightest stars. And there are some spectacular ones, of course.
But our nearest major star, alpha centauri, the yellow guy (below, found near the Southern Cross) is over four light years away from us.
But not every star…
esiegel | March 11, 2011Well, don't you know
I'm gonna skate right through
Ain't nobody do it but me
Nobody but me -The Human Beinz
If you're only a casual watcher of the night sky, you might have no idea what the brightest stars are. Sure, if you're in the northern hemisphere, you probably recognize the Big Dipper,
the bright stars in the constellation Orion (particularly the "belt"),
the Pleiades, otherwise known as the Seven Sisters,
and Cassiopeia, the giant "W".
And if you're farther south, you probably know the extraordinarily bright Canis Major (big dog),
as well as the Southern Cross and the two Pointer…
esiegel | February 17, 2011"I don't know whether these people are going to find themselves, but as they live their lives they have no choice but to face up to the image others have of them. They're forced to look at themselves in a mirror, and they often manage to glimpse something of themselves." -Antonio Tabucchi
It's one thing to look up at our galaxy in the night sky, and see the billions of stars clustered together across the great expanse of space.
Image credit: NASA and Serge Brunier.
But what, exactly, do we look like? It is, perhaps surprisingly, one of the more difficult questions to answer. For example,…