Starship Asterisk*

Today's APOD has been updated because a much better image of Mercury from MESSENGER became available late yesterday that I was not aware of until this morning. It is rare that an APOD is updated during the day, although it has happened a time or two before.

I apologize to readers who were not initially aware of the change, and to our foreign language site translators for the late change.

- RJN

Yes, so I noticed, , , lol.

Excellent! Keep those 'updates' coming!!!

I am looking forward to MESSENGER's images. [Almost as much as I look forward to the ones that come from Cassini.]
It's exciting to think that we're on the threshold of some fascinating discoveries and answers about Mercury.

Yay!

There is so much iron in it that it reminds me of what might be a core remnant of a gas giant that has had ALL it's atmosphere stripped by solar winds.

BMAONE23 wrote:There is so much iron in it that it reminds me of what might be a core remnant of a gas giant that has had ALL it's atmosphere stripped by solar winds.

Whoa! What a thought. Never had any thought that that might exist.

Except do we know what minerals are in the center of our four gas giants?

I think there is speculation that metallic hydrogen might be at the center of jupiter.

Mercury seems to be such a perfect sphere, from a distance. I am sure it would be a paine to drive on, even with a four wheel drive. How did it get to be soround ? Slowly solidifying like being annealed as time flows ?

isn't it dense because as the planets formed... all the mass was kinda orbiting around the sun... so the heavier elements were closer toward the sun, and so that's why mercury has so much iron.

that's why the first four planets are terrestrial and the other four are gaseous.

maybeh... lol.

it's my birthday today too!

isn't that special?

Is it just me? It seems that there are a substantial number of craters shown in the images that have a raised "mound" in the exact center of the crater. I am not aware of these features in images of lunar craters.
Any thoughts anyone? Thanks.
Chromian

chromian wrote:It seems that there are a substantial number of craters shown in the images that have a raised "mound" in the exact center of the crater. I am not aware of these features in images of lunar craters.
Chromian

Lots of lunar craters show that feature. Take a look at Tycho, for example.

I assume that the image that is brought up through the '35 years ago' link in the explanation to the APOD of January 16 2008 is meant to illustrate Solar Flares. . The 1970's were so 8).

Here is the image being talked about, , , guess RJN forgot about the courtesy of posting the link in the first post to a new thread.

http://antwrp.gsfc.nasa.gov/apod/ap080116.html

Is it just me? It seems that there are a substantial number of craters shown in the images that have a raised "mound" in the exact center of the crater. I am not aware of these features in images of lunar craters.
Any thoughts anyone? Thanks.
Chromian

Check with Chuck Wood of the Lunar Pict of the Day at

http://www.lpod.org/

And, why is the image at LPOD so very much better than the one at APOD?!?!?!?!?!?!?!?!?!?!?

One of the pictures returned yesterday from MESSENGER here: http://messenger.jhuapl.edu/gallery/sci ... age_id=120 seems to have a "chain of craters" all connected (WSW of the bright rayed crater).

I know the moon has such chains as well but not as obvious as this one (to my recollection). Is it thought that this is made up from the same object that had broken into fragments before impacting similar to Comet Shoemaker-Levy on Jupiter?

Guess I should have kept my high res monitor, but I see no obvious CS (concise and systematic) types of crater chains. some cohesive splatter patterns possibly.

There are a few CS types of crater chains on Mercury though that I know of.

craterchains wrote:Guess I should have kept my high res monitor, but I see no obvious CS (concise and systematic) types of crater chains. some cohesive splatter patterns possibly.

There are a few CS types of crater chains on Mercury though that I know of.

It seems when I now click on the image it is 'upsidedown' from what I saw before (meaning it is now ENE of the crater with the rays).

the bright crater looks like a double hit. and even maybe a triple hit from the apparent rim geometry. Endless discoveries.

ta152h0 wrote:the bright crater looks like a double hit. and even maybe a triple hit from the apparent rim geometry. Endless discoveries.

I assume you're referring to the mentioned crater in the upper left with the debris rays? I'd say it's actually just a multi-ring crater rim. In large craters it's common for the displaced material around the rim to collapse in stages, causing the concentric ring appearance.

http://www.geologyrocks.co.uk/tutorials/meteor_craters