esiegel | February 27, 2011"Glaciers are almost gone from Glacier National Park." -Donella Meadows
This world is full of beautiful things that are simply awe-inspiring. Some of them are very much man-made, such as this 2007 song by Ricky Skaggs and Bruce Hornsby,
Crown Of Jewels.But others took thousands of years to form.
Image credit: deleted flickr user, of Franz Joseph Glacier in New Zealand.
In many great places all over the world, glaciers are an incredible wonder to behold. Carving valleys, rivers and lakes over thousands of years, they are one of our planets great examples of how slow processes can make…
esiegel | February 25, 2011"Everything has a natural explanation. The moon is not a god, but a great rock." -Anaxagoras
The Moon, as you well know, is one of the spectacular sights of the night sky, especially when it's full.
Image credit: Luc Viatour.
Even those of us with imperfect vision can see differences between the large, dark areas (known as maria) of dried-up lava beds and the bright, white mountainous regions. But through even the smallest of telescopes or binoculars, brilliant features -- invisible to the naked eye -- emerge.
Image credit: Naoyuki Kurita.
One of the largest craters on the Moon,…
esiegel | February 24, 2011"If I have ever made any valuable discoveries, it has been due more to patient attention, than to any other talent." -Isaac Newton
Born the year Galileo died, Isaac Newton is one of the most revered figures in all of physics.
In addition to the work he did on optics, planetary motion and gravitation, Newton is also famous for his three laws of motion, which -- even today -- apply very well to every particle in the Universe. They are:
Law #1: An object at rest will remain at rest, and an object in motion will remain in motion, unless acted upon by an outside force.
What does this mean? It…
esiegel | February 23, 2011"Leading scientists are warning that a massive solar storm could trigger a $2 trillion 'global Katrina' that short-circuits power grids worldwide." -Lesley Taylor
If you've been keeping up with your online news lately, you may have heard that, undoubtedly, an impending Solar Storm will cause hundreds of billions -- if not trillions -- of dollars of damage.
The impending storm has been compared to a global Hurricane Katrina. What's the hullaballoo about?
Last week, the Sun launched forth a powerful Solar Flare, as imaged above by NASA's Solar Dynamics Observatory. What was the big effect of…
esiegel | February 20, 2011"If you once forfeit the confidence of your fellow citizens, you can never regain their respect and esteem. It is true that you may fool all of the people some of the time; you can even fool some of the people all of the time; but you can't fool all of the people all of the time." -Abraham Lincoln
Democracy is hard. There's a reason I became an astrophysicist and not a politician, and it's rare that I talk about politics here. But every once in a while, I see something happening that's so egregious that I have to stand up and speak out for what's right in this world. Bob Marley would likely…
esiegel | February 18, 2011"I'll do my dreaming with my eyes wide open, and I'll do my looking back with my eyes closed." -Tony Arata
Would you believe me if I told you that -- in terms of your own eyes -- you saw better at night than you did during the day?
It's true! But it doesn't have much to do with the amount of light available. When you're looking out at distant objects, you'd love to be able to resolve them with your eyes.
For example, that object in the distance, down the road in the image above? Is it a motorcycle with one headlight, a car or truck with two, or (I hope not!) a train with three?
Well, with…
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,…
esiegel | February 15, 2011"I have announced this star as a comet, but since it is not accompanied by any nebulosity and, further, since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet. But I have been careful not to advance this supposition to the public." -Giuseppe Piazzi
When we think of the planets, most of you think of either eight or nine, depending on whether you count Pluto or not.
But you all know Pluto's story. Eighty-one years ago, a lone astronomer looking at the same few patches of sky, night-after-night, would look for any…
esiegel | February 13, 2011"Dubito ergo cogito; cogito ergo sum."
(I doubt, therefore I think; I think therefore I am) -Rene Descartes
I always try to give you something beautiful completely unrelated to astronomy, physics, or cosmology for the weekend. So if I'm going to talk to you about dark matter, I figured I'd better go for a particularly beautiful song. For those of you who don't know the voice of Regina Spektor, have a good listen, because I think she might be the best young vocalist out there today. Here's her song,
Braille.The first week of this past December was designated to be Dark Matter Awareness Week,…
esiegel | February 11, 2011"It seems like once people grow up, they have no idea what's cool." -Bill Watterson
Well, at least we can all agree on what's not cool. The Sun.
Image credit: NASA, from what looks like the Stereo spacecraft.
With a surface temperature of around 6,000 Kelvins, the Sun is one of the hottest objects that we're all familiar with.
But when it comes to stars, the Sun is merely a "G-type" star. It turns out that there are many types of stars that are -- typically -- more massive, bluer, and hotter than our Sun.
In fact, O-stars, the hottest type, can have surface temperatures over 40,000 Kelvin…
esiegel | February 10, 2011Mr. Harley: Your impatience is quite understandable.
Klaatu: I'm impatient with stupidity. My people have learned to live without it.
Mr. Harley: I'm afraid my people haven't. I'm very sorry... I wish it were otherwise.
-The Day The Earth Stood Still, 1951
People love to talk about the constancy of the natural phenomena. Every 24 hours, from anywhere not within either the Arctic or Antarctic circles, for instance, there's one sunrise and one sunset.
Image credit: Danilo Pivato.
And, of course, there are two high tides and two low tides every day.
The Earth rotates on its axis, and revolves…
esiegel | February 7, 2011"Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover." -Mark Twain
You've all heard of Kepler before, including the exoplanet-finding spacecraft named after the famed 17th Century astronomer. Johannes Kepler is probably most famous for his laws governing the motion of the planets, which cemented the heliocentric model -- and not the geocentric model -- as the best description for the motions of objects in our…
esiegel | February 6, 2011"We are tested academically and the only people who benefit are academics. Everyone doesn't make A's and B's in school - and those people who can't, it doesn't mean you don't have a gift. There are people who are gifted but maybe not academically. You could be an average student but exceptional in other areas." -Pearl Fryar
Every once in a while, I come across something so wonderful that I can't help but stop everything else I was doing and share it with you. Have a listen to New Grass Revival's song from 1989,
You Plant Your Fields,while I introduce you to Pearl Fryar.
Pearl is the subject…
esiegel | February 4, 2011"How'd the moon get here? Look, you pinheads who attacked me for this, you guys are just desperate. How'd the moon get here? How'd the sun get there? How'd it get there? Can you explain that to me? How come we have that and Mars doesn't have it?" -Bill O'Reilly
Once upon a time, humans looked at the tides -- going out and coming in -- and we had no idea what caused them. At high tides, the sea level would rise, and the coast would get swept up by the oceans, while at low tides, the water would recede, leaving tidepools behind.
Image credit: smugmug.com.
Low tides and high tides would each…
esiegel | February 3, 2011Teacher Writes on Blackboard: "The Method of Guessing"
Student: "What! There's a method???????"
Teacher: "Yeah, there's even a proof!" -overheard in a physics grad school
As a physics professor, one of the challenges I face is how to advise young students nearing the end of their undergraduate career on how to succeed in graduate school in physics.
The best I can do is tell them about what I've done myself that's worked for me, and what pitfalls I've seen others fall victim to.
As an undergraduate, my grades were all over the place. I'd take an advanced astrophysics course I was really…
esiegel | February 2, 2011"One creates from nothing. If you try to create from something you're just changing something. So in order to create something you first have to be able to create nothing." -Werner Erhard
One of the oldest adages in existence is you can't get something for nothing, as over a million websites will tell you, including not-so-subtly, cartoonstock.
And, most often when people bring this up to me, it's in an attempt to prove the existence of God -- and the insufficiency of the Big Bang -- by pointing to the Universe.
Image credit: chaospet.
Well, let's take this question as seriously as our…
esiegel | February 1, 2011"With hue like that when some great painter dips
His pencil in the gloom of earthquake and eclipse." -Percy Bysshe Shelley
There may be no greater sight for the naked-eye astronomer than a total lunar eclipse. Normally, we get one or two of these a year, and the same wonderful thing happens at each one.
Image credit: Amateur Astronomical Society of Rhode Island.
If you were standing on the Moon, you'd start to see the Earth begin to cover part of the Sun. As the Earth blocks more and more of the Sun, there would be less sunlight landing on the Moon, and one side of it appears to darken…
esiegel | January 29, 2011"I think it's one of the scars in our culture that we have too high an opinion of ourselves. We align ourselves with the angels instead of the higher primates." -Angela Carter
When I'm getting clear nights, sometimes I'll wake up in the middle of them, and just go and look outside; the allure of the sky is too much. It reminds me of a Sufjan Stevens song,
He Woke Me Up Again.During the winters in Portland, that's -- to put it mildly -- a rare occurrence. But this morning, something almost made up for it. I came across the best Flash Solar System app I've ever seen over at dynamicdiagrams.com…
esiegel | January 28, 2011"We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and 'slipped the surly bonds of Earth' to 'touch the face of God.'"
-John Gillespie Magee, Jr.; spoken by Ronald Reagan after the Challenger tragedy
Twenty-five years ago today, I remember being a student in my second grade classroom. It was a big day, because they were launching the first schoolteacher into space, Christa McAuliffe, along with a crew of NASA astronauts.
Televisions were wheeled into our classrooms so we could watch the launch live on television.…
esiegel | January 27, 2011"It's the great mystery of human life that old grief passes gradually into quiet, tender joy. The mild serenity of age takes the place of the riotous blood of youth. I bless the rising sun each day, and, as before, my heart sings to meet it, but now I love even more its setting, its long slanting rays and the soft, tender, gentle memories that come with them..." -Fyodor Dostoevsky, The Brothers Karamazov
Just last week, I wrote to you about one of the deepest images of the distant Universe, the Hubble Ultra Deep Field.
Image credit: Hubble Ultra Deep Field.
And in particular, how we're able…