Recent content by tony873004

Resonant orbits have a mechanism that ensures their periods have perfect integer ratios. Consider the following analogy. Two cars are on a circular one-lane track. If one of the cars is driving faster than the other, it will eventually catch up to the slower car, and be forced to slow down. It...

Here is a pannable simulation that will run in your browser. It shows all the hyperbolic spacecraft . If you let it run a while, you will see that everything is on an escape trajectory. Don't increase time step past 8192...

Get Horizons position and velocity for any 2 dates and place in simulation. Let's use June 1 and July 1 for example. Import June 1 data. Integrate to July 1, and import July 1 data. You now have 2 spacecraft in your sim. Are the spacecraft in the same place traveling at the same speed? If...

http://orbitsimulator.com/gravitySimulatorCloud/simulations/1515637532274_2009%20MS9.html Pan around. It's not hard to find a perspective that makes it look retrograde, but as Glitch said, 68 < 90, so prograde.

Size, shape and orientation of the orbit will probably be pretty accurate after 1 million years. Position on this orbit will not. That's because a small error in semi-major axis will lead to a small error in period, which will lead to a small error in position. Year after year, this error builds.

Thanks PF_Help_Bot! I feel so much better now.:rolleyes: Honestly, I didn't expect many replies. I learned a while back that if you want replies, you have to phase it like you're starting a conversation. Perhaps even ask a question. The "Like" option is perfect for threads like this. I wonder...

If a helicopter were hovering nearby, positioned directly in front of a star as seen from my yard, they would both have the same RA and Dec, but their positions would be light years apart.

This is a pannable simulation that will run in your browser. It shows where Pioneer 10 & 11, Voyager 1 & 2, New Horizons and ʻOumuamua are, how far they are from the Sun, and their speeds. simulation: http://orbitsimulator.com/gravitySimulatorCloud/simulations/1511746688216_hyperbolic.html...

I made a new simulation where you can pan around. It's similar to the one I already posted, except it includes a path for Oumuamua. The previous one didn't because the code only knew how to superimpose Keplerian ellipses, not hyperbolas. So I had to hand-code Oumuamua's path...

As I updated my Android operating system today, the phone got quite warm. And it was quite cold out this Thanksgiving eve. I found myself clutching my phone to warm my hands.

As this object continues to get observed, its trajectory gets refined. The good news is that with the latest data, Earth only gets pushed out to 2.6 AU.

The Moon stays with the Earth, but its eccentricity is nearly quadrupled. In the simulation, the "camera" is in an unrealistically-fast orbit around the solar system just to show it to you from all sides. That makes it appear as if A2017U1 keeps coming back. If you check "Trails" and run it...

This asteroid, now called ʻOumuamua, is thought to be about 150 meters across. If it was a red dwarf star instead, with a mass of 0.1 solar masses, it would have perturbed all the planets' orbits. Earth would have a semi-major axis of over 7 AU. Here is a simulation of our new solar system...

If there was a single drop on my windshield, I would only conclude that the drop of water likely originated from outside the car. Sprinkler and garden hoses are external to the car. Water drops from them are also more likely to strike a moving car's windshield than its side windows.

You don't need an ensemble of observations. You don't need to see it rain to know that if it does rain, a rain drop is more likely to hit the windshield than the side windows.