Solar System
esiegel | April 1, 2014“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
I know there are many of you out there who miss Pluto "officially" being a planet, and I know that there are a large fraction of you who still count it as one in your hearts. After all, our Solar System is an amazing place, and the discovery of other large objects beyond…
esiegel | January 18, 2014"If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea." -Antoine de Saint Exupéry
It's the end of the week here, so it's time for another Ask Ethan column! Today's question comes from longtime reader and fan Jeremy F., who wants to know about the feasibility of the planned Mars One mission. In particular,
I hope 4 people don't just fly to their death, that would be terrible for my chances of getting to Alpha Centauri or Vega before I die.
No kidding. Let's go back to the…
esiegel | December 18, 2013"In the depth of winter I finally learned that there was in me an invincible summer." -Albert Camus
As the year draws to a close, we approach a very special time of year, at least from an astronomical perspective. This Saturday, December 21st, will mark the Winter Solstice in the Northern Hemisphere (or the Summer Solstice in the Southern), or the date where the Earth's axis is tilted its maximal amount away from (or towards) the Sun, as viewed from an observer in the Northern (or Southern) Hemisphere.
Image credit: Mrs. Snyder at the Seven Hills School.
While it's pretty common knowledge…
esiegel | November 27, 2013“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
So it begins again: the neverending debate about who gets to be a planet and who doesn't. Everyone can bring their own interpretation of the science to the table -- and everyone has their own preferred naming scheme -- but when I think about the Solar System, I try to…
esiegel | November 21, 2013"Mars once was wet and fertile. It's now bone dry. Something bad happened on Mars. I want to know what happened on Mars so that we may prevent it from happening here on Earth." -Neil deGrasse Tyson
Oh, it's true alright, something bad did once happen on Mars. And although there isn't any real danger of that happening to Earth, a little conversation I had earlier this week made me think that it's time to tell all of you a story about our red neighbor, and why it is the way it is today.
You see, when we think about Mars, we think about the smallish, red, desolate world that fascinates us today…
esiegel | November 1, 2013"Galileo got it wrong. The Earth does not revolve around the Sun. It revolves around you and has been doing so for decades. At least, this is the model you are using." -Srikumar Rao
It's the end of the week, so that means its time to take on another one of your questions from the question/suggestion box, and continue our ongoing Ask Ethan series! Even though there's a backlog of hundreds of questions, you should keep sending the new ones in, as all questions are fair game for any segment. This week's question comes from reader Brian Mucha, who asks us:
Where did the sun and planets get their…
esiegel | October 25, 2013"I have just gone over my comet computations again, and it is humiliating to perceive how very little more I know than I did seven years ago when I first did this kind of work." -Maria Mitchell
Well, it's getting close to the end of October, the Moon is waning towards its new phase, and -- at least in the northern hemisphere -- the days are getting shorter and the nights are lengthening. Is there anything unique on its way that's worth watching the skies for? In today's Ask Ethan column, our suggestion comes from longtime reader and commenter Sinisa Lazarek, who inquires:
Since ISON comet is…
esiegel | October 18, 2013"If you are writing any book about the end of the world, what you are really writing about is what's worth saving about it." -Justin Cronin
Well, it's Friday again, and that means it's time to dip into the question/suggestion box, and see what you've come up with for me. This week's Ask Ethan comes from our reader Michael Acosta, who wants to know about the end of the world. Not, mind you, the way the world is actually likely to end, but in a way that would be satisfying to an aspiring science fiction writer.
In this wonderful science fiction book I am writing, there is a subplot involving…
esiegel | October 17, 2013"It is not when truth is dirty, but when it is shallow, that the lover of knowledge is reluctant to step into its waters." -Friedrich Nietzsche
Although the innermost planets, from Mercury through Saturn, were known since ancient times, it's only since the advent of the telescope that we've discovered what really lives in our Solar System. Over the past four centuries, the wonders of not only the distant Universe, but also our nearby neighborhood, have been uncovered in spectacular detail.
Image credit: NASA and – I believe – G. Bacon (STScI).
The third and fourth largest planets were…
esiegel | October 9, 2013"Even in hindsight, I would not change one whit of the Voyager experience. Dreams and sweat carried it off. But most of all, its legacy makes us all Earth travelers among the stars." -Charley Kohlhase
In the early days of space exploration, it was quite a feat just to get up and out of Earth's atmosphere. There's are two good, simple reason for that, of course: first, it takes a lot of energy to go up that high...
Image credit: Nathan Bergey of http://psas.pdx.edu/orbit_intro/.
and second, if you don't get your spacecraft moving really fast, you're just going to fall back to Earth once you…
esiegel | October 2, 2013"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science." -Charles Darwin
There are problems with science today, no doubt. With all the knowledge we've accumulated about the Universe, from the smallest subatomic scales to the farthest recesses of deep space, there are still realms and regimes where our best theories fail, where the predictions and the data don't match, and where no known explanation is sufficient for the phenomena that shows up…
esiegel | September 12, 2013"The great oak of Astronomy has been felled, and we are lost without its shadow." -Subrahmanyan Chandrasekhar, on the passing of Jan Oort
In our new semi-regular series, readers from all over the world (and in low-Earth orbit, too, because why not!) are invited to send in their questions and suggestions for a chance to have them answered here on this blog! Today, our question comes from Robert Meegan, who asks,
Have any Oort Cloud objects been detected in situ, as opposed to when they whipped through the inner solar system as comets? I would presume that any detection would need to be…
esiegel | September 11, 2013"Like all animals, human beings have always taken what they want from nature. But we are the rogue species. We are unique in our ability to use resources on a scale and at a speed that our fellow species can't." -Edward Burtynsky
It's really a romantic notion when you think about it: the heavens, the Milky Way, is lined with hundreds of billions of stars, each with their own unique and varied solar systems.
Image credit: 湖北直行便 of AstroArts, via http://www.astroarts.jp/photo-gallery/photo/13870.html.
But beyond that -- in addition to the stars -- there are hundreds of billions of planets…
esiegel | August 30, 2013"Being told about the effects of climate change is an appeal to our reason and to our desire to bring about change. But to see that Africans are the hardest hit by climate change, even though they generate almost no greenhouse gas, is a glaring injustice, which also triggers anger and outrage over those who seek to ignore it." -Sigmar Gabriel
With all of the scientific issues subject to politicization in this world, there's arguably none that raises such strong emotions as the issue of global warming and climate change. This is the final installment of a three-part series on how one could…
esiegel | August 29, 2013"We make the world we live in and shape our own environment." -Orison Swett Marden
If you had never heard of global warming before, how would you figure out whether it's real or not? And if it is real, how would you figure out what humanity's role in it is? To answer this, I've decided to do a three-part series on how you'd go about figuring this out, putting aside all politics, economics, opinion and any other non-scientific factors. If you missed part 1, you can check it out here; today we're going to build on that and talk about what determines the temperature of a planet with an…
esiegel | August 28, 2013"There is no question that climate change is happening; the only arguable point is what part humans are playing in it." -David Attenborough
It's been a long time since I've written anything on this blog about global warming, climate change, or most Earth-based environmental topics in general. After all, I'm a physicist -- an astrophysicist in particular -- and although I'm well-versed in the physics of the Earth and in science in general, it's not my particular area of expertise.
Image credit: NASA, Johnson Space Center, Apollo 17 crew.
Recently, I've had a number of requests to take a…
esiegel | August 9, 2013“Next to reasoning, the greatest handicap to the optimum development of Man lies in the fact that this planet is just barely habitable. Its minimum temperatures are too low, and its maximum temperatures too high. Its day is not long enough, and its night is too long... These factors encourage depression, fear, war, and lack of vitality. They describe a planet, which is by no means perfectly devised for the nurturing or for the perpetuation of a higher intelligence.” -James Thurber
It's been just about three years, now, since the first announced discovery of a planet in another star system…
esiegel | August 8, 2013"What was most significant about the lunar voyage was not that men set foot on the Moon, but that they set eye on the Earth." -Norman Cousins
What would life on Earth be like without the Moon?
Our nearest neighboring body in the cosmos has a profound effect on us. It's helped not only shape our evolution, biologically, but has shaped the entire evolution of our planet. Created some 4.5 billion years ago -- when our planet and Solar System were still in their infancy -- when a roughly Mars-sized planetoid crashed into a young proto-Earth, the Moon has been our companion-in-orbit ever since.…
esiegel | July 31, 2013"You can't exactly bake a man to your specifications... A hybrid of Einstein, Tarzan and Inge Meysel doesn't exist." -Peer Steinbruck
Of course, if you create enough chances, all the things that could eventually happen will come to pass. This is as true for human beings as it is for the physical Universe. And for our planet, our nearest major neighbor in the Universe -- the Moon -- provides us with a huge variety of sights, if only we're willing to wait.
Image credit: Doug Zubenel.
Every 27.3 days, the Moon makes a complete orbit around the Earth, traveling a full 360° through space. As it…
esiegel | July 26, 2013"That's why I enjoy taking myself out of my own element, my own comfort zone, and hurling myself out into the unknown. Because it's during those scary moments, those unsure steps taken, that I am able to see that I'm like a comet hitting a new atmosphere: suddenly I illuminate magnificently and fire dusts begin to fall off of me... I'm a shooting star. A meteor shower. But I'm not going to die out. I guess I'm more like a comet then. I'm just going to keep on coming back." -C. JoyBell C.
Here in the Solar System, meteor showers are one of the things we take for granted on Earth. In particular…