Solar System
esiegel | July 3, 2013"To disagree leads to study, to study leads to understanding, to understand is to appreciate, to appreciate is to love. So maybe I'll end up loving your theory." -John Wheeler
Out there in the Universe, there's a lot to marvel at. Over billions of years, gravity has attracted different portions of the expanding Universe together into large superclusters and filaments, each made up of clusters, groups, and individual galaxies separated by great cosmic voids.
Image credit: Sloan Digital Sky Survey, 2dF Galaxy Redshift Survey, and Millenium Simulation.
From the observations of this structure…
esiegel | June 2, 2013"...because today, with cameras as pervasive as they are, there is no such thing really as professional photographers." -Marissa Meyer
Before you get irate, I don't actually agree at all with that quote above; I have no talent for photography at all and a tremendous respect for those who do, and who cultivate it to produce something beautiful. So this weekend, the most appropriate song I could find for you was by a group known as Camera Obscura, and their rather dark ballad,
Your Picture.
Why do I bring up photography today? Because one of my blog's biggest fans, Felicity, runs a fun little…
esiegel | May 8, 2013"No valid plans for the future can be made by those who have no capacity for living now." -Alan Watts
"They do not see what lies ahead, when Sun has faded and Moon is dead." -J.R.R. Tolkien
One of the most amazing facts about the Universe is that, despite only having spent a few hundred years studying the fundamental constituents and forces of what makes us up, humanity has been able to accurately figure out just what all this actually is.
Image credit: ESO / S. Brunier.
The laws of nature are almost completely understood in a few, very important senses. We know that our Universe is about…
esiegel | April 17, 2013“We are much closer today to being able to send humans to Mars than we were to being able to send men to the moon in 1961, and we were there eight years later. Given the will, we could have humans on Mars within a decade.” -Robert Zubrin
Of all the planets in the Solar System beyond our own, none has captured our imagination quite like Mars has.
Image credit: NASA, via http://photojournal.jpl.nasa.gov/jpeg/PIA02570.jpg.
From science-fiction fans to scientists and everyone in between, our understanding of the red planet is presently greater than it ever has been in the past. With multiple…
esiegel | March 6, 2013"The atoms come into my brain, dance a dance, and then go out - there are always new atoms, but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
Here you are, a human being, a grand Universe of atoms that have organized themselves into simple monomers, assembled together into giant macromolecules, which in turn comprise the organelles that make up your cells. And here you are, a collection of around 75 trillion specialized cells, organized in such a way as to make up you.
Image credit: J. Roche at Ohio University.
But at your core, you are still just…
esiegel | February 15, 2013“Don't wake me for the end of the world unless it has very good special effects.” -Roger Zelazny
It's always the ones you least expect that get you the worst, it seems. I went to bed last night excited that Asteroid 2012 DA14, a 200,000 ton asteroid, was going to pass within just 28,000 km (or 17,000 miles) of Earth's surface, which would make it the closest pass of an asteroid that large that we've ever observed.
Image credit: NASA / JPL Near-Earth Object Program Office.
I thought that would be the best way to celebrate today, which would be Galileo's 449th birthday. After all, it was…
esiegel | February 13, 2013"It does no harm to the romance of the sunset to know a little bit about it." -Carl Sagan
I would argue the exact opposite, in fact: the beauty of a sunset, in all of its varieties and variations, is only enhanced the more you know about it.
Image credit: Dan Schroeder, via Picasa.
The next time you watch the Sun descend through the sky, towards the horizon, you might marvel at how the Sun remains the same size all the way down. At just slightly over half-a-degree, the Sun appears to drop at a constant rate throughout the afternoon and into early evening.
But there are some small changes…
esiegel | February 8, 2013"Night, when words fade and things come alive. When the destructive analysis of day is done, and all that is truly important becomes whole and sound again." -Antoine de Saint-Exupery
When you look out into the Universe, what is it that you typically think of? Do you think of reliable, fixed stars and constellations? The vast expanse of the Milky Way, with its memorable dust lanes and amorphous shapes?
Image credit: Wally Pacholka of http://www.astropics.com/.
The unchanging nature of the points of light in the sky?
Image credit: Roth Ritter (Dark Atmospheres), of the double cluster in…
esiegel | January 30, 2013"Concentrate all your thoughts upon the work at hand. The sun's rays do not burn until brought to a focus." -Alexander Graham Bell
Imagine a beautiful, clear day. The Sun is shining, the skies are clear, and you couldn't ask for a nicer day.
Image credit: © 2012 Free HD wallpapers.
All of a sudden, the Sun itself appears to brighten, just for a brief amount of time, like it released an extra burst of energy. That night, some 17 hours later, the most spectacular auroral display ever brightens the night in a way you never imagined.
Image credit: Jónína Óskarsdóttir.
Workers across the…
esiegel | January 27, 2013"In any field, find the strangest thing and then explore it." -John Archibald Wheeler
Sometimes, things get difficult. Sometimes, there are challenges you have to face that you never even expected, much less were prepared for. And sometimes, it seems like there's no point in even holding on to hope that things will get better. But as long, as The National would tell you, as you're no
Runaway,
you've still got something worth striving for. Even if there's something newer, shinier, and more powerful than you.
Image credit: NASA / Hubble Space Telescope.
Even on Mars.
Nine years (and three…
esiegel | January 5, 2013"Stuff your eyes with wonder, live as if you'd drop dead in ten seconds. See the world. It's more fantastic than any dream made or paid for in factories." -Ray Bradbury
It wasn't all that long ago -- back when I was a boy -- that the only planets we knew of were the ones in our own Solar System. The rocky planets, our four gas giants, and the moons, asteroids, comets, and kuiper belt objects (which was only Pluto and Charon at the time) were all that we knew of.
Image credit: NASA's Solar System Exploration, http://solarsystem.nasa.gov/planets/index.cfm.
But these were just the worlds…
esiegel | December 27, 2012"Tell me what you feel in your room when the full moon is shining in upon you and your lamp is dying out, and I will tell you how old you are, and I shall know if you are happy." -Henri Frederic Amiel
Tonight is a special night, although not for the reasons you may think. Yes, it's just a few days after Christmas and before the new year, but tonight is the night of the Full Moon closest to the winter solstice.
Image credit: Judy Stone-Goldman.
Up here in the northern hemisphere (above the Tropic of Cancer), December 21st corresponds to the winter solstice, or the shortest day in terms of…
esiegel | December 20, 2012"I hope you feel things you never felt before. I hope you meet people who have a different point of view. I hope you live a life you’re proud of, and if you’re not, I hope you have the courage to start all over again." -Eric Roth, screenwriter
Forget the prognosticators, the fortune-tellers and the mediums. Pay no mind to the soothsayers, the prophets, the augurs and diviners. The seers see no more than any other sighted person, the omen-interpreters have been superseded by the ornithologists, the psychics made obsolete by the scientists.
Because if doomsday ever does approach, we won't be…
esiegel | December 19, 2012"Death comes to all, but great achievements build a monument which shall endure until the sun grows cold." -Ralph Waldo Emerson
In the great cosmic ocean, there's only one planet that we know -- for certain -- has the right conditions and history to result in intelligent life: our own.
Image credit: NASA, from the Space Shuttle, for Sun-Earth Day 2008.
Life -- or even intelligent life -- may be possible in environments vastly different than our own: around different classes of stars, at different temperatures, and even with different molecules and/or chemical elements.
But we know for…
esiegel | December 12, 2012"I have this one little saying, when things get too heavy just call me helium, the lightest known gas to man." -Jimi Hendrix
Hendrix, as I told you once before, was almost right. We know of helium, conventionally, as the lighter-than-air gas that we fill balloons, blimps and zeppelins with in order to quickly and easily "defy gravity" here on Earth.
Image credit: Jonathan Trappe.
At least defying gravity is what it appears to do. But what's really going on is that helium is simply a very low-density gas. Our atmosphere, a mix of mostly Nitrogen (N2) and Oxygen (O2) gases, has an average…
esiegel | November 30, 2012"You don't drown by falling in the water; you drown by staying there." -Edwin Louis Cole
Our Solar System is -- at least from our perspective -- the most well-studied system of planets, moons, asteroids and comets in the entire Universe.
Image credit: Olaf Frohn, from earlier in 2012.
And in this system, the closest planet to our Sun, Mercury, was also one of the most poorly understood planets until very recently. Because Mercury is so close to the Sun, it's very difficult to view it under good conditions with a telescope; the risk of ruining your optics by exposing them to direct sunlight…
esiegel | November 28, 2012"Summer ends, and Autumn comes, and he who would have it otherwise would have high tide always and a full moon every night." -Hal Borland
Of course you know the danger that would befall us if the Earth ever got too close to the Sun, as the Perry Bible Fellowship shows, atop. But have you ever stopped to think about the Moon in our skies, and what would happen if the Earth and Moon were closer together than they actually are?
Image credit: NASA / Galileo mission.
While photos such as this -- from the Galileo spacecraft -- accurately show the relative size and illumination of the Earth and…
esiegel | November 21, 2012“We live in an atmosphere of shame. We are ashamed of everything that is real about us; ashamed of ourselves, of our relatives, of our incomes, of our accents, of our opinions, of our experience, just as we are ashamed of our naked skins.” -George Bernard Shaw
All that is real about ourselves is nothing to be ashamed about; quite to the contrary, it's something to be eminently thankful for. This very existence is all we have, and while it's minuscule compared to the entire Universe, it required the entire Universe to bring us to the point where it's possible for us to exist.
What do I mean by…
esiegel | November 2, 2012"The important point is that since the origin of life belongs in the category of at least once phenomena, time is on its side. However improbable we regard this event, or any of the steps which it involves, given enough time it will almost certainly happen at-least-once. And for life as we know it, with its capacity for growth and reproduction, once may be enough." -George Wald
That there's an amazing story of life's evolution on Earth is a scientific certainty. The evidence is encoded in the nucleic acid sequences of every living organism ever discovered, and the history of life on this…
esiegel | September 18, 2012"Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not." -Galileo Galilei
All of science is rooted in the idea that natural phenomena can be explained naturally, and that if we want to know how anything in the Universe works, all we need to do is ask the Universe the right questions, and the answers will appear.
So what about the question of the night sky, and why it appears to rotate the way it does?
Image credit: Peter Michaud (Gemini Observatory), AURA, NSF.
There are two straightforward explanations for…