Astronomy
milhayser | April 27, 2011
The universe remains a mysterious place, and one of the biggest mysteries confronting astronomers today is that "the amount of mass we can see through our telescopes is not enough to keep galaxies from spinning apart." Since the 1930's, this shortfall has been covered by dark matter, a hypothetical substance which has never actually been observed. On the Weizmann Wave, we can consider an alternative called MOND (Modified Newtonian Dynamics) which "posits that gravity works differently on the intergalactic scale." In fact, University of Maryland researcher Stacy McGaugh recently published…
esiegel | April 22, 2011"We came all this way to explore the moon, and the most important thing is that we discovered the Earth." -Bill Anders, Apollo 8 Astronaut
This Earth Day, I think -- for anyone interested in space, astronomy, or the Universe -- gives us perhaps the best opportunity to look back on our planet as we understand it now, having traveled so far away from it.
It was only, believe it or not, back in the 1940s that we first photographed our planet from high enough up to directly observe that, in fact, the Earth is curved!
The above image, from 1948 in space over New Mexico, was the first panorama…
esiegel | April 20, 2011"You may hate gravity, but gravity doesn't care." -Clayton Christensen
What's the deal with gravity, dark matter, and this whole "lensing" business anyway? You've probably heard that energy -- most commonly mass -- bends light. And perhaps you've seen an image or two like this one to illustrate that.
Image credit: ESA, NASA, J.-P. Kneib and Richard Ellis.
Above is the great galaxy cluster Abell Cluster 2218. But those giant, stretched arcs you see? Those are actually background galaxies that get distorted and magnified by the giant cluster.
As the light leaves its source, the mighty gravity…
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 | April 17, 2011"The loss of the night sky is most troubling for children. Whole generations of kids in cities and suburbs are growing up seldom if ever having seen the milky way and what a sky full of thousands of stars look like." -Timothy Ferris
While Dave Chappelle will tell you that everything looks better in slow motion, when you're looking at the night sky, you need a lot going for you these days. Paramount among them, as the Easy Star All-Stars might tell you (covering Pink Floyd), is
Time.Because if all you do is look up from within your city, you're likely to see something like this.
A pretty…
esiegel | April 11, 2011"Life's but a walking shadow, a poor player, that struts and frets his hour upon the stage and then is heard no more; it is a tale told by an idiot, full of sound and fury, signifying nothing." -William Shakespeare
Ahh, the glorious shadows of our Universe. Everywhere that sunlight is blocked gives us shadow.
Image credit: Kaguya (Selene).
For the Earth, of course, this results in night and day each time the Earth rotates.
The Earth, though, is also tilted on its axis a significant amount, by about 23.5 degrees. When a pole tilts towards the Sun, it receives continuous daylight, while when…
esiegel | April 5, 2011"Where there is an observatory and a telescope, we expect that any eyes will see new worlds at once." -Henry David Thoreau
This past weekend, the Astronomy Picture of the Day was a remarkable shot of the giant spiral galaxy NGC 6872, taken by the Gemini Telescope. (It's not Hubble, but Gemini is pretty impressive in its own right!)
One look at this galaxy should tell you that it's an interacting galaxy in the process of a collision! How should you be able to tell?
The distorted shape is a big clue; normal galaxies don't have extra-long tails stretched out in a line through space! That's…
esiegel | April 3, 2011Intel Science Talent Search Winner: Mr. Bush, please save Hubble.
Then-President Bush: Is Hubble in trouble?
Oh my, yes, for those of you who don't know, Hubble is, in fact, in trouble once again. To set the mood, I've got one of the best songs about it: Ray LaMontagne's
Trouble.
For the uninitiated, Hubble -- imaged here from the Space Shuttle Atlantis -- is not only the telescope that changed the Universe, it is the single most scientifically productive piece of equipment of all time. That's right, as Neil de Grasse Tyson wrote,
More research papers have been published using its data than…
esiegel | March 31, 2011"It took less than an hour to make the atoms, a few hundred million years to make the stars and planets, but five billion years to make man!" -George Gamow
Some people are never satisfied. After I wrote last time on the odds for cosmic inflation, I started noticing a flurry of comments on an older post about alternatives to the big bang. So, might as well go back to the basics, and ask what the odds are that the Big Bang is correct! Let's start by taking a look at what's out there in the Universe.
Image credit: Hubble Space Telescope.
Sure, we've got stars surrounding us: hundreds of…
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 26, 2011"There is a pleasure in the pathless woods,
There is a rapture on the lonely shore,
There is society, where none intrudes,
By the deep sea, and music in its roar:
I love not man the less, but Nature more." -Lord Byron
All over the world, Earth Hour has fallen, and it's about to, imminently, here in my part of the world. For a song to take you through this post, I've got a (Peter Rowan?) folk classic performed by The Be Good Tanyas in their own unique style,
Midnight Moonlight.Perhaps, if you're one of the lucky ones with clear skies, you might be able to notice something you hardly ever get…
esiegel | March 25, 2011"Some scientists claim that hydrogen, because it is so plentiful, is the basic building block of the universe. I dispute that. I say there is more stupidity than hydrogen, and that is the basic building block of the universe." -Frank Zappa
Oh yeah, Zappa? Well, let me show you what hydrogen can do!
With just one proton and one electron, hydrogen is not only the simplest of all the atoms in the Universe, it's also the most abundant: over 90% of all the atoms in the Universe are hydrogen atoms!
How could such a small thing possibly have anything interesting to tell us about the entire Universe…
esiegel | March 23, 2011"I came from the country, and when I came to the city, I was ridin' high, you know. I was seeing more lights than I ever dreamed to shine in the world. 'Cos where I came from, there wasn't too many lights. Bugs made a lot of light, but after that there wasn't no lights." -John Hunter
John Hunter should have been at a higher latitude! Because if you're fortunate, at a high enough latitude (either north or south), the following sight will sometimes greet you in the night sky.
Image credit: Thundafunda.com.
In the northern hemisphere, we call it the Aurora Borealis, while the southern gets the…
esiegel | March 17, 2011"Don't tell me the moon is shining; show me the glint of light on broken glass." -Anton Chekhov
Ahh, Chekhov, you old sour puss, what do you have against the brilliance of our Moon?
Beautiful in our sky, the Moon typically takes up half-a-degree in the night sky, where it's by far the largest and brightest object visible to the naked eye (well, for those of you who can't see the full Andromeda galaxy with your naked eye). But the Moon actually varies in its apparent size in the sky! If you photograph the Moon when it appears to be at its largest, it actually appears about 14% bigger than…
jdupuis | March 14, 2011Here's a hint. Never, ever, ever put the following sentence in any non-fiction book you are writing:
This is dull stuff. (p. 165)
Testify!
An object lesson on non-success for popular science books to compare and contrast with an object lesson for success in popular science books.
But, to be fair, the book under consideration isn't really a popular science book. J.L. Heilbron's new Galileo is a scholarly scientific biography of Galileo and as such shouldn't really be compared to popular science books.
On the other hand, it was a topic I expected to really enjoy but I did end up struggling…
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 | March 10, 2011"All truths are easy to understand once they are discovered; the point is to discover them." -Galileo Galilei
Ever since the time of Galileo, Jupiter has been an amazing sight for skywatchers. With its four large moons, even the smallest of amateur telescopes provide amazing sights.
In fact, if you watch Jupiter's four large Moons over the span of a few hours, you're likely to discover the same exact thing that Galileo did.
You can see that Jupiter's moons orbit around Jupiter! Looking through a larger telescope, like the video above was shot using, you can actually see the shadows of…
esiegel | March 3, 2011"Old men and comets have been reverenced for the same reason: their long beards, and pretenses to foretell events." -Jonathan Swift
Last week, I showed you the new, highest-resolution mosaic ever made of the near side of the Moon.
And I also showed you a small, somewhat unusual feature that I named "Snakey."
Snakey isn't all that impressive, of course. What might strike you as unusual, however, is that it appears to be a chain of craters, found close together, making a (roughly) straight line!
But there is a far better example. Much thanks goes to our reader, Tom Scrace, who was looking at…
esiegel | March 1, 2011"There's an old saying about those who forget history. I don't remember it, but it's good." -Stephen Colbert
Let me start by telling you a story about an old problem. Take a look at the planet Mercury, one of the five planets (not counting Earth) visible in our night sky to the naked eye.
And I can see some of you at home squinting at your screen, asking why I'm showing you a picture of the Moon right after sunset. Well, Mercury's in that picture, I promise. Let me make it a little easier for you.
No less a naked-eye astronomer than Copernicus had difficulty seeing the planet Mercury, and…
milhayser | February 28, 2011
On Life at the SETI Institute, Dr. Franck Marchis shares the latest results from Kepler, a telescope in an Earth-trailing heliocentric orbit which keeps a distant eye on 156,453 stars. Kepler watches for tell-tale reductions in brightness, which "could be due to the transit of an exoplanet passing between its star and us." As of Tuesday, Kepler has identified 1202 likely new exoplanets, tripling the number of known worlds beyond our solar system. These results suggest that out of the 200 billion stars in our galaxy, "several hundred million of them could have an exoplanet with a surface…