'New Horizons' detects first major 'Ultima' puzzle

WHY doesn't the object show signs it's rotating?

Even though scientists determined in 2017 that the Kuiper Belt object isn't shaped like a sphere – that it is probably elongated or maybe even two objects – they haven't seen the repeated pulsations in brightness that they'd expect from a rotating object of that shape. The periodic variation in brightness during every rotation produces what scientists refer to as a light curve.

"It's really a puzzle," said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. "I call this Ultima's first puzzle – why does it have such a tiny light curve that we can't even detect it? I expect the detailed flyby images coming soon to give us many more mysteries, but I did not expect this, and so soon."

What could explain the tiny, still undetected light curve? New Horizons science team members have different ideas.

Link

a reply to: JimOberg

Can't get your link to work here...

Okay, I think this one is working.

Well... I'm surprised no one is considering alien megastructure yet.

a reply to: vinifalou

Link

pluto.jhuapl.edu...

maybe this will work.

link fixed

Can't rule out eclipsing binaries eating/absorbing smaller solar bodies in a possible very tight orbit with one another; or just the one star orbiting a black hole; possibly too small to be swallowed by it; and yet gravity strong enough it can't escape it either, also being cause for it collide with smaller bodies, in doing so.

Hurrah for first puzzles!

May there be many more.

a reply to: JimOberg

Sorry JO, there have been multiple observations of UT and there is no dust or moons in orbit.

ATS link.

That was news that they are taking the closest flyby (even closer than Pluto) because there is no dust. See the Wikipedia link for all the observations made.

It could be two spheres in a kinda binary orbit. Cool thing is it will only take a couple of weeks to find out!!

Happy New Year!

originally posted by: Phage
Hurrah for first puzzles!

May there be many more.

Yes! The New Horizons researchers are excitedly getting the Holiday presents they hope for in the form of much-wanted mysteries.

As comedian Dara O'Briain points out "Of course science doesn't know everything, otherwise it would stop".

Guessing that it's very smooth and round.

If the body(or bodies) are uniform, or nearly uniform in surface color then the light reflection curve would be minimal. The period of the curve would indicate the speed of rotation as well....and I've heard nothing of that metric yet. But then, we will know more in a week I am sure.

Go Science!

Always on the sharp edge of knowledge....

thick dust?

originally posted by: wildespace
Guessing that it's very smooth and round.

Problem with that theory is the observed star occultation results recently, showing indication of either contact or close binary form.

phys.org...

Somebody painted it.

Chances are, the two lobes of Ultima Thule orbit around a barycenter between them, in a plane at or near right angles to the New Horizons probe. That would make them return about the same amount of reflected light, at any time.If that's not the case, we do have mystery to solve.

originally posted by: Ross 54
Chances are, the two lobes of Ultima Thule orbit around a barycenter between them, in a plane at or near right angles to the New Horizons probe. That would make them return about the same amount of reflected light, at any time.If that's not the case, wedohave mystery to solve.

This scenario seems plausible to my layman's brain.

So what you're saying is that the amount of reflected light from the object would not change that much if the same amount of reflected surface is always pointed toward the light detecting instrument as the object rotates -- even if that rotation was of a dumbbell-shaped object.

Right, or two separate bodies orbiting close to one another. The only problem with this scenario seems to be the improbability of the the two objects just happening to orbit in the correct plane, with respect to the New Horizons probe.

a reply to: Ross 54

Equally as unlikely as the axis of rotation of a spherical(ish) body being aligned with the spacecraft?

a reply to: Ross 54

Improbability. Not impossibility.

I luvs me a mystery!!!

This one should be readily solved in a week or so...

originally posted by: Phage
a reply to: Ross 54

Equally as unlikely as the axis of rotation of a spherical(ish) body being aligned with the spacecraft?

Perhaps even more so. Two objects must assume one specific, narrowly defined orbital plane, as against: one object must have its axis pointed in a particular direction.