Comments on Mike Brown's Planets: Moon shadows galore

Hi :)I was just examining Enceladus and they said ...

2009-03-22T23:12:00.000-07:00

Hi :)

I was just examining Enceladus and they said it had a geometric albedo of greater than one. That was pretty confusing. Apparently what was happening there is that ice can reflect light directy back to it's source, like those highway reflectors you see in the middle of the road.

Here is a very beaurtiful shot of Saturn at opposition, directly opposite the the Sun from the Earth, and two other shots taken with the same techniques at other times:

http://www.astro.virginia.edu/~av4n/satfinal.jpg

Notice the dramatic difference in the brightness of the rings.

Haumea, of course, is not at present lined up with the Sun and the Earth.

I was wondering how this phenomenon affects this project? Any comment?

Hi, Mike :)Good luck on your observing run Saturda...

2009-01-28T00:09:00.000-08:00

Hi, Mike :)

Good luck on your observing run Saturday. I hope you can get the first observations of the dance of the moon shadows. I wish somebody had taken advantage of some of the other opportunities but they are gone now.

I was wondering if perhaps I could ask for the locations on Earth where these events can be seen. Then perhaps if we have a friend in the area we could maybe prevail upon them to get the local institution to participate and enjoy.

This great adventure of discovery is a treasure to watch, I can only imagine the excitement of actual participation. We who await breathlessly to see if the real facts fit out sometimes vivid imaginations are, you may rest assured, extremely appreciative of your efforts.

Meantime those of us whose glasses are held together by string may content ourselves with playing with Wikipedia guestimates and seeing if we can do something with them. They say Haumea has a surface area of 20 X 10^7 km^2. So how much must the mass flow of any geysers in the system have to keep it painted crystalline white?

I would guess that an accumulation of a millimeter per million years should do the job. That woud be compacted snow, I would imagine the Eskimos, who have a number of different words for snow, would have to make up a new one for this. Anyway, 2 X 10^7 km^2 X 10 ^6 m^2/km^2 X .001 m = 2 X 10^10 m^3 water, X 1000 kg/m^3 = 2 X 10^13 kg. There are about 30 million seconds in a year (1 significant figure here) so there are about 3 X 10^13 seconds in a million years. So it takes a geyser with a mass flow of about 2/3 of a kilogram per second to keep Haumea painted. That's a lot less intense than the spectacular fountains of Enceladus which spew a few hundred kilograms per second of water vapor.

"Santa" might have been a good name after all, what with his association with snow!

I just learned learned the Chinese characters for ...

2008-11-13T12:22:00.000-08:00

I just learned learned the Chinese characters for Haumea mean something like Rock Goddess Star. How cool is that. Joan Jett would be proud.

I am glad to hear that news and read it here in yo...

2008-11-12T00:25:00.000-08:00

I am glad to hear that news and read it here in your post. I also have great interests on astronomy and astrophotography like you. You may want to visit my recently discovered site and see what they are doing with tiny cheap camera. See here, http://zookland.com/

Is the seperation enough to consider Haurnea and i...

2008-10-30T16:44:00.000-07:00

Is the seperation enough to consider Haurnea and its moons as point sources for the sake of simulating their motions?

JPL Horizons doesn't have info on TNO moons. I'd love to simulate this in Gravity Simulator. Is there any place I can get their R & V vectors, and masses?

Hi, Mike, this is Great News! We get to see just ...

2008-10-27T18:59:00.000-07:00

Hi, Mike, this is Great News! We get to see just exactly what Haumea's diameter and albedo are.

(As second poster I'll dispose of what will surely be commented on. Watch out for those typos).

I can now make a falsifiable prediction. I predict that Haumea's albedo will be even higher than your previous estimates. I base this not on supernatural stuff, but on the detection of a large amount of crystalline water ice on the surface.

I believe it is snowing on Haumea even as we speak. It doesn't take much. About a centimeter every 10 million years will keep the surface fresh and bright. It's snowing on Enceladus and that body has an amazing 99% albedo.

The snow has the same source as at Enceladus - Namaka is getting beat up by tidal forces. Your article notes the extreme perturbation of Namaka's orbit by Hi'iaka and this should be enough to pour enough heat into Namaka to feed a slow geyser.

I've thought Haumea was the lost moon of Triton since noticing when I flew a binary pair of equal sized objects past Neptune on the GravitySimulator, that sometimes they collided. Triton had to have been a binary to have lost enough angular momentum with respect to Neptune to be captured. I believe now that Haumea is the object that absorbed that excess angular momentum.

Anyway it's great to be able to put out a falsifiable hypothesis. That's the difference between science and pseudoscience.

I guess the subject of a bet might come up but I believe it is illegal to bet on the internet according to the laws of Texas and anyway I have almost no money. But a gentleman's bet is acceptable. Any takers?

Can you collaborate with any of the teams searchin...

2008-10-27T17:07:00.000-07:00

Can you collaborate with any of the teams searching for transiting exoplanets, since it is kind of the same sort of a measurement?