a thoughtful web.
Good ideas and conversation. No ads, no tracking.   Login or Take a Tour!
comment by kleinbl00
kleinbl00  ·  3175 days ago  ·  link  ·    ·  parent  ·  post: Pluto has a tail!

I enjoy your enthusiasm immensely. Could you elaborate on this?

    The problem with that is that there is no, at least no known, way to pump energy into Pluto like there is with Europa, Enceladus, Titan, even the earth.




user-inactivated  ·  3175 days ago  ·  link  ·  

Sure. Europa has a liquid ocean of water under its ice. But Europa is small and should be frozen solid. So you need a source of energy to melt that water ice. It turns out that the tug of gravity from Jupiter, Io and Ganymede create tides in Europa that pull and tug on it; this generates energy as the internals flex and rub up against itself. In the earth, the moon, creates tides that we see at the ocean, but it also creates tides in the earth itself, some 2-3 feet at the equator. Enceladus has a pool of liquid that is heated from the push and pull of the gravitational tug of war between Saturn and Titan.

Pluto, however, has no source of tidal energy input. Pluto and Charon are in a gravitational equilibrium; there is no tug of gravity inputting energy into either body, or at least there does not appear to be. Because Pluto and Charon are tidally locked to each other both in revolution and rotation, there is no push-pull like in the other small bodies listed above.

So, why is there so much gas above the surface of Pluto? Where did it come from? Why is the surface of Pluto so young and crater free?

And yea, this excites me. I've seen Pluto with my own eyes through a 25" telescope as nothing more than a very faint dot that barely moved over two nights. Now, that dot is a whole world with strange geology. I'm going to do an outreach event tonight showing 200-300 people Saturn, and I expect a lot of Pluto questions as well.

kleinbl00  ·  3175 days ago  ·  link  ·  

    Because Pluto and Charon are tidally locked to each other both in revolution and rotation, there is no push-pull like in the other small bodies listed above.

Ahhh! I did not know this. That does make it interesting. Thank you.

    I've seen Pluto with my own eyes through a 25" telescope as nothing more than a very faint dot that barely moved over two nights.

I had a 10" Dobsonian back in the day; I looked into the logistics of looking at Pluto and decided that it was well beyond my means. I think the biggest glass I've ever looked through was a 20". So this begs the question - what do you do and where do you do it? because about the only regret I have in moving from New Mexico to Washington was the lack of easy deep sky...

user-inactivated  ·  3175 days ago  ·  link  ·  

I moved from the California desert to the Ohio Valley. Every time there is something to look at in the sky I debate moving back west, then the bills come due and I am glad that I am here. There is something to be said for a $350 mortgage payment that all the clear dark sky in the world can't overcome.

Our Astronomy Society does a lot of outreach trying to keep membership up enough to fund the fun stuff we like to do. We own 40 acres out about an hour away from town that is dark enough to see M13, M3 and M31 with the naked eye on good nights. The bad news is that the last year or so has been the worst weather wise in 12 years I have been out here. We are right under the jet stream, its hot as ass and twice as humid. When it gets a bit cooler and starts getting dark at 8PM again I do stuff with the library as well.

As for where, I have an agreement with the city and two different grocery stores that I can set up my scope and let people look. Tonight I am going to set up in a city park and hope for clear enough skies to get a few hundred people a chance to look at Saturn. The moon is too close to the sun to let randoms look through the scope, but next week will be first quarter and that will be a big draw during the day and we can hit 1000 people a day looking through a scope. Out of those 1000, 100 will take a flier, 20 will contact the facebook group and 1 or two will send messages about either "hey come to our school!" or will actually join the club. But I get to talk about space and nerd out for a few hours, so that makes me happy.

Pluto is considered a "challenging" object for anything under a 12" scope. If you have a camera and a good mount, a 4" scope can get an image, assuming you know what you are doing. There is a group of people who have been able to visually observe Charon! They were in the mountains, over 9000 feet above sea level and using 36" dobsonians, but they were able to watch Charon revolve around Pluto over a week. This is one of those things where knowing that the object exists helps you more than you care to admit.

I'm going to a star party in West Virginia next month in the shadow of the NRAO and get to go on a full site tour. but damn if I don't miss star gazing at 8500 feet in the Sierras. That was an experience that everyone needs to do at least once.

disinformation  ·  3173 days ago  ·  link  ·  

Although they are tidally locked, that estimate is at first order. How much energy do higher order instabilities contribute to energy generation? Is it something sufficient to keep in motion something that has been previously set?

user-inactivated  ·  3172 days ago  ·  link  ·  

That is an interesting question I did not think of before. I guess that depends on how long ago Pluto and Charon became tidally locked. When I see Dr. Harold Geller next month I'll ask that question. Maybe we will have more data and can at least start to guess.

disinformation  ·  3172 days ago  ·  link  ·  

I cant wait to hear more results from the data!