We’ve got your back, Joseph—that’s our job at the MPC

Wow! Does this mean you’ve got a massive great laser (in the terawatt range) pointing at the sky to take out anything that comes our way?

(PleasesayyesPleasesayyesPleasesayyesPleasesayyesPleasesayyesPleasesayyes!)

We’ve got your back, Joseph—that’s our job at the MPC!

—JL Galache
Minor Planet Center

Regarding using it to view comets, is that because of Swift’s rapid slewing capability?
I can’t remember where, but somewhere I read that Hubble and certain other orbital telescopes simply can’t “keep up” with some inner solar system objects.

@#7 JL Galache: Yes, I am assuming the change in its trajectory due to the Earth’s mass is small, and I’m ignoring the Moon, and also assuming the parallax due to Earth’s rotation over 25 mins to be very small, not to mention I left out the Yarkovsky effect…

Also the perturbation caused by the planets. And galactic tides. And the Poynting–Robertson effect

/just loves a good geekout

@#9 JL Galache: Cool! It’s good to know that there are people keeping tabs on these things

But SOT = ??? Please.

@8. Georg : I take it that’s a Poe?

@9. JL Galache : Thanks for that informative comment. Cheers!

(Sorry couldn’t resist.) Actually they really did – the speed at which stuff like this comes out these days impresses me. As does being able to watch things like spacecraft launches and planetary and asteroidal encounters live from the other side of the planet on a computer as good as a TV.

Great video and write up – thanks BA & the Swift team.

For some serious orbit-changing dynamics, check out the close encounter we had with 2011 MD back 0n June 27th:

http://minorplanetcenter.net/blog/too-close-for-comfort-the-near-earth-approach-of-2011-md/

—JL Galache
Minor Planet Center

The Swift observation lasted 25 mins. According to my calculations, 2005 YU55 was travelling at ~49,400 kph, so it would have covered ~20,580 km during this time, which is about 0.002% of the total ~952 million km of its orbital path around the Sun. Furthermore, given its orbit is quite elliptical (e = 0.43), and that it was travelling along the “long” part of the ellipse, it’s fair to say that its path was essentially a straight line during the Swift observation.

As for the asteroid having its path affected by the Earth, we’ll have to wait a few days for further observations to calculate its new orbit and figure out how much the change was. In any case, the Earth would be changing the orbit via gravitational force, that’s essentially tugging the asteroid with a vector pointing straight towards Earth, towards *us*, so (on this video’s small timescale) the projected path of the asteroid against the celestial sphere would not change and we would still observe it flying in a straight line, even if its 3D motion were affected. Swift’s orbital altitude is ~600km, so it would essentially “see” the same thing. I hope this made sense.

Yes, I am assuming the change in its trajectory due to the Earth’s mass is small, and I’m ignoring the Moon, and also assuming the parallax due to Earth’s rotation over 25 mins to be very small, not to mention I left out the Yarkovsky effect…

Sorry for the Geek out!

—JL Galache
Minor Planet Center

And this is a comment with infinite profundity…

Ryan

The asteroid is comparable to the distance to the Moon at that point. The Moon’s path is curved enough that it goes around the Earth once a month, and the asteroid is moving much faster so that it turns even less. Swift’s path turns around Earth every 90 minutes or so.

If you plotted a perfectly straight path and the asteroid’s path and the Moon’s paths seen by Swift, you could see that they are different, but they would all have the same general shape.

Do you know that a straight line mathematically speaking is the particular case of a circumference with infinite radius?

C’mon, you KNOW that’s going to be a headline somewhere.

Isn’t the asteroid passing close enough to the Earth to have it’s orbit affected by our gravity? Wouldn’t that mean that it’s path as it passes us would bend a bit more? (or less, I guess)