Starship Asterisk*

by **orin stepanek** » Wed Aug 23, 2006 10:40 pm

No problem JohnD! I'm anxious so see Achip's animation.
Orin

by **astro_uk** » Wed Aug 23, 2006 10:01 pm

Nice animation.

The reason the asteroids haven't all coalesced is simply because gravitationally they are so puny, all of the asteroids put together weigh much less than the mass of the moon. When you realised that this mass is then spread over such a huge area you can see that it would take an incredible amount of time to assemble anything larger than Ceres. You also have the problem that Jupiter tends to cause asteroids to avoid certain orbital radii otherwise there orbits become unstable and they are attracted to Jupiter, the asteroid belt is actually several belts separated by gaps. This adds to the fact that asteroids are generally seperated by huge distances.

by **JohnD** » Wed Aug 23, 2006 9:27 pm

Orin,
Thank you for the Hubble video of Ceres!

Surely that is a 'better' view?
The one chosen by APOD has 30x30 (approx) pixels.
To show the complete globe must involve at least ?2-3 times more pixels/datapoints, even if that video is based on such blocky images as the APOD, smoothed like I did and then in-betweened (?).

The full rotation includes a featureless area that occupies about three quarters of a hemisphere. Terra Incognata? Heere bee Dragons? Or just a bit that didn't get measured?

Also note; the video is a year more recent than the APOD view!
John

by **harry** » Wed Aug 23, 2006 7:11 am

Hello All

I have always wandered why there are so many small objects between Mars and Jupiter.

If ceres was part of the pack, why did it not grow from the impacts.
It had enough time.

by **orin stepanek** » Wed Aug 23, 2006 1:09 am

hubble video!

http://imgsrc.hubblesite.org/hu/db/2005 ... cktime.mov

Orin

by **orin stepanek** » Tue Aug 22, 2006 11:02 pm

http://imgsrc.hubblesite.org/hu/db/2005 ... _print.jpg
Maybe all of Ceres is like an icecap!

I wish the fly by was soon.
Achip, Hi! Hubble has an animated picture of Ceres. I still want to see yours though.
Orin

by **BMAONE23** » Tue Aug 22, 2006 9:29 pm

Could be Mount Hooverist

by **ckam** » Tue Aug 22, 2006 8:41 pm

orin stepanek wrote:Could the white spot maybe be like a polar cap?

could it be alien city lights? doesn't make much sense on the day side, though...

by **iamlucky13** » Tue Aug 22, 2006 8:40 pm

BMAONE23 wrote:Maybe if we crashed Ceres into Mars, Mars would become habitable as Ceres would add the necessary volume to have a near Earth gravity and an abundant water supply.

My understanding is that part of the reason that Mars does not have a significant amount of water (and a rather thin atmosphere) is because of its lack of a significant magnetic field. The magnetic field prevents the suns radiation from effectively blowing it away from the planet, like a strong breeze increasing evaporation of water from clothes on the laundry line (sort of). Mars theoretically saw a similar accumulation of water from comet bombardment or other means as Earth did in the early solar system, but there's not much there today. Bumping Ceres into Mars wouldn't change that.

Also, I think Ceres is only a relatively small fraction of Mars' mass...on the order of 10% or less, so the mass gain wouldn't be that dramatic.

More practically, that would be pretty chaotic and the new body probably wouldn't have a stable surface for thousands of years. Plus environmentalists generally raise a stink every time somebody tries to smash a giant asteroid into a planet.

I'm kind of interested to see your animation aichip

by **BMAONE23** » Tue Aug 22, 2006 5:04 pm

Maybe if we crashed Ceres into Mars, Mars would become habitable as Ceres would add the necessary volume to have a near Earth gravity and an abundant water supply.

by **aichip** » Tue Aug 22, 2006 4:20 pm

Using the four images in the APOD picture, I have created a solid model of Ceres. I am now animating it so I can post a link. The bright spot appears to be northwest of a depression or valley and seems to be higher than the surroundings.

As soon as the project is done, I will post the details here.

by **orin stepanek** » Tue Aug 22, 2006 3:50 pm

Largest Asteroid May Be 'Mini Planet' with Water Ice

--------------------------------------------------------------------------------

View all images

Observations of Ceres, the largest known asteroid, have revealed that the object may be a "mini planet," sharing many characteristics of the rocky, terrestrial planets like Earth. Ceres' mantle, which wraps around the asteroid's core, may even be composed of water ice. The observations by NASA's Hubble Space Telescope also show that the asteroid has a nearly round shape like Earth's and may have a rocky inner core and a thin, dusty outer crust. The four Hubble images of Ceres [above] were taken over a 2-hour and 20-minute span, the time it takes the Texas-sized object to complete one quarter of a rotation. One day on Ceres lasts 9 hours. The bright spot that appears in each image is a mystery.

Read the full press release text

Credit: NASA, ESA, J. Parker (Southwest Research Institute), P. Thomas (Cornell University), and L. McFadden (University of Maryland, College Park)

Find more news releases:
Could the white spot maybe be like a polar cap?

Orin

by **ckam** » Tue Aug 22, 2006 3:39 pm

it should be downsized - not blurred - until each square block is 1x1 pixels.

by **Orca** » Tue Aug 22, 2006 2:46 pm

Nuts!

by **orin stepanek** » Tue Aug 22, 2006 1:23 pm

more views of Ceres.
http://hubblesite.org/newscenter/newsde ... s/2005/27/
Under the rules that planets would have to be large enough to be an orb would qualify Ceres to be called a planet. Originally I believe that Ceres was called a planet before being demoted to asteroid status.

Orin

by **harry** » Tue Aug 22, 2006 6:59 am

Hello All

Re link

Ceres: Asteroid or Planet?
http://antwrp.gsfc.nasa.gov/apod/ap060821.html

Ceres, at about 1000 kilometers across, is the largest object in the main asteroid belt between Mars and Jupiter. Under the newly proposed criteria, Ceres would qualify as a planet because it is nearly spherical and sufficiently distant from other planets

by **astro_uk** » Mon Aug 21, 2006 8:39 pm

Hi JohnD

there are many technical answers to this question but the simple answer is that by blurring the image you have effectively lost resolution. By blurring the image you have replicated the effect of the Earths atmosphere on any image taken on Earth of the sky. The blurring has smoothed out features visible on the HST image so they are no longer as prominent (most notably the white spot). In Black and White images like this, the colour indicates the number of photons collected by the detector, by smoothing the image you make any detections of features in the image much less statistically significant.

This image is perhaps a bad example because it seems like there is so little information in the images. However if you took an image of a field of stars and smoothed that progressively more strongly, eventually you would begin to find that stars start to disappear. They get smeared into the night sky.

by **JohnD** » Mon Aug 21, 2006 8:23 pm

This APOD is billed as the 'best image yet of Ceres.

But I can download it straight into MS Photodraw, that every XP owner has, and engage the 'blur and sharpen' tool to get this. It looks a lot more like an asteroid, aka planet, than that blocky image.

I'm not better at image manipulation than the Hubble team, but how is my version worse, when it looks better?
What information has been lost by blurring it?

John

Starship Asterisk*

Ceres - the 'best image yet' (APOD 21 Aug 2006)

Post a reply

Expand view Topic review: Ceres - the 'best image yet' (APOD 21 Aug 2006)

solid model of Ceres in the works

Ceres - the 'best image yet' (APOD 21 Aug 2006)