Comment on The fastest ever human-made object keeps breaking its own speed record
MossyFeathers@pawb.social 1 year ago
It’s too bad they can’t fling the probe in the opposite direction once it’s done with the sun. I know it’s instruments are probably tuned specifically to take measurements of various solar phenomenon from close-up and probably aren’t sensitive enough to be useful for any deep space science, but it’d be cool to use that speed to launch it on an escape trajectory and see how long it takes to catch up to the Voyager probes.
So, it doesn’t work the way you think.
It’s only going that fast because it’s near the sun. You can’t use that to go elsewhere. It had to lose a lot of energy to get as close to the sun as it is. It would need to gain that back to even earth.
I’m really blanking on a way to explain this concisely and I can’t explain orbital mechanics in a Lemmy post.
Drop a ball. It goes fastest just before and after it hits the ground, and slows down until it gets back to near the height you dropped it from
The probe is the ball, and slingshotting around the sun is like bouncing off the ground. The potential energy (height of ball/distance from sun) gets converted to and from kinetic energy (speed).
That’s a pretty good answer. I was definitely overthinking it.
Seeing an annular eclipse is an excellent application of orbital mechanics! Enjoy!
Glad you are having fun. I never want to fly through Vegas again. That airport was outrageous, even by airport standards.
Thanks! I didn’t think about the fact that it’d lose velocity to gravity as it gets further away.
I wonder if you could slingshot a probe by firing it to fly by the sun and then shedding mass at its perihelion. The idea being that the craft would be mostly dead weight, increasing the force exerted on the craft by the sun’s gravitational pull. Once you reach the perihelion, you eject the mass behind the craft so that there’s less force acting on the craft as it moves away from the sun.
👍. I like science.
You wouldn’t just drop mass along side you in space. It would just continue to float along beside you.
You definitely have the throw it behind you, like you said, but that’s what rockets do. They throw mass behind them to make them move forward. That’s a rocket.
When you throw mass behind you at one point in your orbit, you raise the height of your orbit on the opposite side of the orbited object (this is simplified).
So you’re basically right, it’s partially about the mass of the object, but it’s mostly any the firing of the rocket.
You’ve got some pretty good intuition though.
It even has a name, the Oberth effect
Just “shedding mass” won’t do it. Uncouple a payload from the mass of the ship at perihelion, and they will just float along together, side by side in their original orbit.
But, if that “mass” is “rocket fuel”, and you “shed” it by burning it behind you, you’ve got the right idea. As the other commenter said, the Oberth effect means the closer you are to the sun, the faster you are moving, and the greater the effect that burning will have.
Yes, the Oberth effect means that firing a rocket at the periapsis changes your orbit more than at any other point in the orbit.
dave@feddit.uk 1 year ago
PSP is travelling at 394,736mph. Voyager 1 is about 15 billion miles away and travelling at about 35,000mph.
Time taken to catch up t is roughly 394736t = 15000000000 +35000t or about 4.75 years.
fiat_lux@kbin.social 1 year ago
Thanks for the math! Here's hoping we can fling the records of our civilisation far enough out for another civilisation to learn about our demise. And not, like, just accidentally flinging it into a burning star or space imperialist Klingons or something. Even though that would be poetically appropriate too.
Ghoti_@lemmy.world 1 year ago
So like .06% of light speed?
sin_free_for_00_days@sopuli.xyz 1 year ago
I had a couple more zeroes when I did the math. I’m not sober though.