Foreign object now leaving solar system

[jkn]

Here are some (hopefully) accurate numbers that blow my weekend mind:

Object arrival speed: 25.5 km/s
Object departure speed: 44 km/s

It got a 72.5 % boost from that slingshot around the sun. I knew this is how things end up going fast, but that is a lot! Makes me want to know how it ended up going that fast, and how many other meetings with stars it had to have. But without knowing what got it going in the first place, that would be hard.
#orbitalMechanicsRookie

Hey, can Kerbal Space Program reproduce this orbit? I really need to get KSP...

Welp: it wasn't that fast. Turns out the Helios probes hold the spacecraft record at 70.22 km/s... Or a quarter million km/h. Or Mach 205.71. Take that, um, visitors. ;-)
Edit: And Helios hit 0.0002357 times the speed of light.

I don't know what those speeds mean. For example slingshot around Jupiter does not change speed of a satellite relative to Jupiter. Speed will change relative to Sun, Earth, Pluto,... So slingshot around the Sun does not increase speed relative to Sun. For example a star and a rock are coming 10 km/s towards the Sun from same direction. A rock goes around the Sun and back to direction it come from. It will have very high speed when close to Sun, but speed will drop to back 10 km/s when far away. It was rest relative to that star. Now it is traveling 20 km/s towards it.

Escape velocity - Wikipedia
Escape v from Sun at Earths orbit is 42.1 km/s, From Mars orbit 34.1 km/s. If a rock is at rest far away from the Sun and starts falling towards the Sun, it will have speed 34.1 km/s at orbit of Mars, 42.1 km/s Earth, 67.7 km/s at Mercury.

 

[e-FTW]

I don't know what those speeds mean. For example slingshot around Jupiter does not change speed of a satellite relative to Jupiter. Speed will change relative to Sun, Earth, Pluto,... So slingshot around the Sun does not increase speed relative to Sun. For example a star and a rock are coming 10 km/s towards the Sun from same direction. A rock goes around the Sun and back to direction it come from. It will have very high speed when close to Sun, but speed will drop to back 10 km/s when far away. It was rest relative to that star. Now it is traveling 20 km/s towards it.

Escape velocity - Wikipedia
Escape v from Sun at Earths orbit is 42.1 km/s, From Mars orbit 34.1 km/s. If a rock is at rest far away from the Sun and starts falling towards the Sun, it will have speed 34.1 km/s at orbit of Mars, 42.1 km/s Earth, 67.7 km/s at Mercury.

This makes a lot of sense to me, but I am quoting the figures NASA/JPL posted here: News | Small Asteroid or Comet 'Visits' from Beyond the Solar System

 

[Topher]

For example slingshot around Jupiter does not change speed of a satellite relative to Jupiter.

Sure it will. Particularly if you use the correct term, velocity.

A rock goes around the Sun and back to direction it come from.

Not this rock. Rocks on elliptical orbits will go back where they came from (and return later). Rocks on parabolic orbits will head sort of back somewhere in the direction they came from (and never come back). Rocks on hyperbolic paths will head off in some entirely new direction, and never return.

Thank you kindly.

 

[Ulmo]

Speed of light is 299,000 km/s

Edit: or a little more precisely 299,792,458 m/s

.3Gm/s, or 299Mm/s, or 299,792km/s, to round. Why do so many people put so many 000's in metric? Wasn't metric supposed to be easier, not harder?! Not only can't we use our body to measure it, but then they just make it nuts to use. @oneday, I'm not complaining to you, but to the world.

 

[oneday]

.3Gm/s, or 299Mm/s, or 299,792km/s, to round. Why do so many people put so many 000's in metric? Wasn't metric supposed to be easier, not harder?! Not only can't we use our body to measure it, but then they just make it nuts to use. @oneday, I'm not complaining to you, but to the world.

I always blew it with my sig. fig.’s in physics class.

 

[cronosx]

.3Gm/s, or 299Mm/s, or 299,792km/s, to round. Why do so many people put so many 000's in metric? Wasn't metric supposed to be easier, not harder?! Not only can't we use our body to measure it, but then they just make it nuts to use. @oneday, I'm not complaining to you, but to the world.

First of all, using your body is the most stupid thing in the world, since every body is different and 20-30% it's normalityand it can lead you to a totally wrong decision ( and we are talking about adult! ).
If we put it in children i can see how it's like: "Hey little son, it's 2 feet", then he calculate with it's feet and say "oh no! is 5 feet", "no son, you need to calculate the feet of big man, not a little one" "oh.. it's ok, it's not at all confusing! thank you dad!"

Second, you don't really "pay" the 0, and confronting two measure in the same km/s or similar is easier like "it's 5km/s vs it's 500kms/s", it's easy to say "it's 100 times faster", and converting from one unit to another it's simple, it's 5km/s? add 3 zero and here you go it's 5000m/s, easy and simple, no calculation, can be done mentally etc, why should i need to do some math to compare inch to feet? it's absurd.
I don't need math to compare mm to cm, or mm to mt or similar, but you do, and it's silly, useless, and it get you nowere.

 

[jkn]

I tried to make as simple post as possible to get main point trough: Somebody has simplified too much and turned message into bs:

"Object arrival speed: 25.5 km/s
Object departure speed: 44 km/s"

Why do you think velocity is correct and speed is not?

I'll use velocity as vector and speed absolute value of it.

For example slingshot around Jupiter does not change speed of a satellite relative to Jupiter (direction of velocity will change). Speed will change relative to Sun, Earth, Pluto,... So slingshot around the Sun does not increase speed relative to Sun (direction of velocity will change). For example a star and a rock are coming 10 km/s towards the Sun from same direction. A rock goes around the Sun and roughly back to direction it come from. It will have very high speed when close to Sun, but speed will drop to back 10 km/s when far away. It was rest relative to that star. Now it is traveling 20 km/s roughly towards it.

 

[e-FTW]

Can someone simply come to an agreement (I know it is hard) about how the JPL explained what just happened:
"
The CNEOS team plotted the object's current trajectory and even looked into its future. A/2017 U1 came from the direction of the constellation Lyra, cruising through interstellar space at a brisk clip of 15.8 miles (25.5 kilometers) per second.

The object approached our solar system from almost directly "above" the ecliptic, the approximate plane in space where the planets and most asteroids orbit the Sun, so it did not have any close encounters with the eight major planets during its plunge toward the Sun. On Sept. 2, the small body crossed under the ecliptic plane just inside of Mercury's orbit and then made its closest approach to the Sun on Sept. 9. Pulled by the Sun's gravity, the object made a hairpin turn under our solar system, passing under Earth's orbit on Oct. 14 at a distance of about 15 million miles (24 million kilometers) -- about 60 times the distance to the Moon. It has now shot back up above the plane of the planets and, travelling at 27 miles per second (44 kilometers per second) with respect to the Sun, the object is speeding toward the constellation Pegasus.
"

 

[jkn]

Can someone simply come to an agreement (I know it is hard) about how the JPL explained what just happened:
"
The CNEOS team plotted the object's current trajectory and even looked into its future. A/2017 U1 came from the direction of the constellation Lyra, cruising through interstellar space at a brisk clip of 15.8 miles (25.5 kilometers) per second.

The object approached our solar system from almost directly "above" the ecliptic, the approximate plane in space where the planets and most asteroids orbit the Sun, so it did not have any close encounters with the eight major planets during its plunge toward the Sun. On Sept. 2, the small body crossed under the ecliptic plane just inside of Mercury's orbit and then made its closest approach to the Sun on Sept. 9. Pulled by the Sun's gravity, the object made a hairpin turn under our solar system, passing under Earth's orbit on Oct. 14 at a distance of about 15 million miles (24 million kilometers) -- about 60 times the distance to the Moon. It has now shot back up above the plane of the planets and, travelling at 27 miles per second (44 kilometers per second) with respect to the Sun, the object is speeding toward the constellation Pegasus.
"

I see nothing wrong in that text. A/2017 U1 had speed 25.5 km/s when it was far away from the Sun. Its speed increased when it fell towards Sun. Suns gravity turned it around (less than 180⁰). Because it is climbing away from Sun its speed is slowing down. It was 44 km/s when article was written. Speed will drop back to 25.5 km/s when it is far away for the Sun. That takes years.

Slingshot effect can give permanent increase of speed.