THE CORRIDOR OF FIRE

This is an interesting loop of the corridor of fire. In the nuclear war which hasn't happened, the brightest lights were going to infinitely brighter for a series of instant and then darken to nothing at all once the fires burned out. It makes it easier to visualize when seen at night. Very glad it didn't happen.

BY JOVE

One never really thinks about how the solar system works. Here's a good shot of what Jupiter does for the inner solar system.  Cheerfully stolen from Traditional Vibe.

papatulus:

tsunamiwavesurfing:

giflounge:

The orbit of Jupiter protects the Earth from asteroids.

a silent guardian, a watchful protector

lol look at mercury go that wild bastard

(via uuniversee)

I happen to think it looks a lot like a Wankel rotary engine.

A LITTLE PI GOES A LONG WAY

Someone asked the Jet Propulsion Lab how much pi they used in their orbital calculations. Here's the answer provided by the  director and chief engineer for NASA's Dawn mission, Marc Rayman.

Here's what he said: To start, let me answer your question directly. For JPL's highest accuracy calculations, which are for interplanetary navigation, we use 3.141592653589793. Let's look at this a little more closely to understand why we don't use more decimal places. I think we can even see that there are no physically realistic calculations scientists ever perform for which it is necessary to include nearly as many decimal points as you present. Consider these examples: 

The most distant spacecraft from Earth is Voyager 1. It is about 12.5 billion miles away. Let's say we have a circle with a radius of exactly that size (or 25 billion miles in diameter) and we want to calculate the circumference, which is pi times the radius times 2. Using pi rounded to the 15th decimal, as I gave above, that comes out to a little more than 78 billion miles. We don't need to be concerned here with exactly what the value is (you can multiply it out if you like) but rather what the error in the value is by not using more digits of pi. In other words, by cutting pi off at the 15th decimal point, we would calculate a circumference for that circle that is very slightly off. It turns out that our calculated circumference of the 25 billion mile diameter circle would be wrong by 1.5 inches. Think about that. We have a circle more than 78 billion miles around, and our calculation of that distance would be off by perhaps less than the length of your little finger. 

We can bring this down to home with our planet Earth. It is 7,926 miles in diameter at the equator. The circumference then is 24,900 miles. That's how far you would travel if you circumnavigated the globe (and didn't worry about hills, valleys, obstacles like buildings, rest stops, waves on the ocean, etc.). How far off would your odometer be if you used the limited version of pi above? It would be off by the size of a molecule. There are many different kinds of molecules, of course, so they span a wide range of sizes, but I hope this gives you an idea. Another way to view this is that your error by not using more digits of pi would be 10,000 times thinner than a hair! 

Let's go to the largest size there is: the visible universe. The radius of the universe is about 46 billion light years. Now let me ask a different question: How many digits of pi would we need to calculate the circumference of a circle with a radius of 46 billion light years to an accuracy equal to the diameter of a hydrogen atom (the simplest atom)? The answer is that you would need 39 or 40 decimal places. If you think about how fantastically vast the universe is — truly far beyond what we can conceive, and certainly far, far, far beyond what you can see with your eyes even on the darkest, most beautiful, star-filled night — and think about how incredibly tiny a single atom is, you can see that we would not need to use many digits of pi to cover the entire range.

So, there you go, a little pi goes a long way.

THE VIEW FROM OLYMPUS

If not for electricity, it would be hard to tell anybody lives here. It is sometimes hard to believe how much of the world still rations electricity or does without. When you think about it, the very words used to describe electricity come not from the last century, but the one before that. Some of them were born into an even earlier century.

André-Marie Ampère
Charles Augustin de Coulomb
Alessandro Volta
Charles Proteus Steinmetz

There is, here, an almost detectable disdain for the echelons of modern liberal government but I admire the people who hammered out the hidden agreements about the use of space. We and the Russians exploited orbit without any binding agreements because retaliation, but not all were so inclined. As it happens, few countries were technologically virtuous enough and militantly indifferent to cost. We're happy with what we have but it could have been so much more.

It's amazing to me that airmen alive today saw many of the cities shown in the images above, aflame from high above them after they dropped tons of bombs on them. Orbit was a battlefield. And, by the Grace of God, a peaceful one.

Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal. 

Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to dedicate a portion of that field, as a final resting place for those who here gave their lives that that nation might live. It is altogether fitting and proper that we should do this. 

But, in a larger sense, we can not dedicate -- we can not consecrate -- we can not hallow -- this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us -- that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion -- that we here highly resolve that these dead shall not have died in vain -- that this nation, under God, shall have a new birth of freedom -- and that government of the people, by the people, for the people, shall not perish from the earth. 

Abraham Lincoln
November 19, 1863

The third light of the world owes its existence to a tiny handful of people who were nurtured by a renaissance that happened in just one place on the planet. It's rather nice to see it finally spreading its wings and embracing the entire planet.

THE PIONEERS LONG FALL IN WINTER

Everybody remembers the pioneers.

The Lament for Icarus

BLUE ORIGINS

Color me impressed. As I read about McCain's response to United Launch Alliance's refusal to bid on putting defense satellites into orbit because they can't get an exemption from the requirement to use 'made in America' rocket engines, I suspect the opportunity Bezos saw in putting together his launch team years ago is about to pay off.

It's funny the article made no mention at all about the imbecility of putting U.S. Military Space Operations at risk every time we launch a satellite into space using a a defective Russian rocket engine. You'd think there'd be some thought put into actually surrendering all of our access to space and giving sole custody of orbit to Russia. Well, you would unless you were a complete imbecile.

Even if the Russian government does not cut off the supply to ULA of imported RD-180 engines, the US Congress, with emerging support from the Air Force, has come around to a view that it would not be advantageous to the US government to start up a US production line to produce the RD-180.

HAPPY VETERAN'S DAY

Best wishes to all for a very peaceful Veteran's Day. Take an idle moment to see all of the places Veteran's have been during just the last 100 years or so. They get around, they really do. Watch in full screen for best effect.

Use your mouse to kill the little annoying text boxes in the video.

JOURNEY TO SPACE

If you live near an Imax theater. Keep your eyes peeled for Journey To Space 3D. We saw it at the IMAX in the Smithsonian's Air and Space Museum. It was amazing. It was hard to believe how many of the video clips I've inserted here over the years were filmed in 3D. When I get home I'll have to look at them again with my 3D glasses on.

It's hard to believe  how huge the solar system is and yet how small it would be if we had continuous boost engines to take us to planets far away.

Still on walkabout.

ROSETTA IMAGES

There are some fascinating space related sites that describe and show the Rosetta Comet mission.

The close-in photos of the comet are here.  The details of the orbit mechanics for the complete mission are rendered in a fascinating 3D graphic located here.

DRAT

Although nobody was killed or injured this represents a real setback for what remains of our so-called space program. Of course, it being a NASA product, it uses a Russian engine from a country currently under embargo for its behavior in Ukraine.

Why anybody would be surprised to see an American spacecraft with Russian engines explode is a continuing mystery.

IF SATURN APPROACHED

From House of Eratosthenes

ORBITAL HUMOR

Ars Technica has a video up on their page which shows the movement of the Space Shuttle Transport System Transport (STS) Aircraft as it moves from the airfield to the Houston Space Museum. The video is interesting to people like me. I wondered at the puckish humor painted on the 747. Snapshots from the short video below:

The shuttle attachment pintle on top of the 747 where the orbiter goes

The Schematic for people who cannot read

ICONIC PICTURES OF THE 21ST CENTURY

100 iconic photos of the century so far. They missed a few but all were good.

It's hard to believe it has only been 14 years. It feels longer.

Dwarf Combat Bread in Action

Red Circle Around Earth

FOUND YOU

From the incomparable folks at The Planetary Society.

Earth setting in the Gale Crater.

TOTAL LUNAR ECLIPSE EARLY TOMORROW MORNING

From our friends at the York County Astronomy fanciers:

As usual with stellar phenomena here in MetroParkCentralis, we expect complete and total-soul-destroying cloud coverage from one horizon to the next. Dammit!

With rain.