X-1 Cygni (astronomy science series)

not far from Forest Road 271 in Park County. Parking where a spur of the 4x4 trail is now closed. Not far from the end of 271.

Discovered in 1964, this compact source of X-rays radiating from Cygnus (a large summer-time constellation. The Northern Cross is an asterism of Cygnus) is the first known black hole.

Black holes were hypothesized in the early 1900’s : Einstein’s Theory of Relativity stated that the space-time continuum could be bent by gravity. On places with low gravity, such as the Earth, which has a gravitational pull of 9.78 meters per second squared, it’s fairly easy to reach escape velocity and go into orbit: which is why we have satellite T.V., accurate weather forecasts, and astronauts on the I.S.S. But in order to escape Earth’s surface and get high enough to orbit, a spacecraft must get going pretty fast. (The I.S.S., which is still inside Earth’s gravity- it just happens to be in free fall. An orbit can be thought of as falling and missing. The I.S.S is missing the Earth at 17,500 miles per hour) Escape velocity from Earth is generally accepted as 11.2 kilometers per second. Getting off the moon, which is less massive, you need to be going only about 2.4 kilometers per second.

The sun, which is a million more times the size of the Earth is also much more massive- it contains 99.98 percent of the mass in the entire Solar System; escape velocity from the Sun would be 35.6 kilometers per second. But our Sun is on the small end of average when it comes to stars. Huge stars have huge escape velocities.

But there is a problem. The universe has a speed limit, and that is 299,792.458 kilometers per second. Going back to Einstein’s Theory, Karl Schwarzschild did a number of calculations, and came up with the idea that a star might be so massive, that nothing, not even a photon of light, could go fast enough to escape the star's gravity. The universe could be full of massive stars like this- stars so big that space would bend back on itself around them.

But how do you detect a star like that? You can’t see it- no light is coming from it.

That’s where x-rays come in. X-rays can no more escape the gravity of a black hole any more than any other kind of light can. But outside the black hole, stuff is falling. Gas, dust, planets, stars being torn apart, all being pulled toward the black hole. If the stuff is not falling straight in, and falls into a decaying orbit, it spins around the outside of the black hole faster and faster. All of this stuff falling inward begins to crash against each other causing friction, heating to enormous temperatures, and emitting x-rays.Most of these x-rays are emitted the wrong way, and eventually become part of the black hole, too. But some of them go the other way, and are far enough away from the black hole that they can escape. And if they escape, and happen to be pointed toward the Earth, Viola! We can detect them!

All of this was well and good, and debated fiercely until 1964 when an x-ray source in Cygnus was discovered.

If you would like to know more about black holes, and X-1 Cygni in particular, there is a great wiki article here http://en.wikipedia.org/wiki/Cygnus_X-1

Originally I thought this science series would be a power trail, but things being the way things are, these astronomy-themed caches are not very power-trail-ish. Instead, the first half can be found along Lake George’s Forest Rd 271. This is a 4x4 trail; please do not attempt with a regular car! Terrain and difficulty ratings are for people who drive to the cache locations; if you hike or mountain bike, of course the D/Ts will be different.

There will be a mixture of regular sized and small caches to start. We have a lot of peanut-butter jars to repurpose. The key is to have fun! And stay safe!

cache is a short walk and climb from Forest Road 271 (near the end of the long spur). Nice views if you climb to the top; no need to, though. Cache is near base of the granite outcropping. Some signal bounce here

Congrats to jherber for bragging rights: FTF on 08/27/13!