Ceres bright spots sharpen but questions remain

Ceres Bright Spots Sharpen But Questions Remain
Latest image released by NASA of the white spots in the 57-mile-wide crater on the dwarf planet Ceres. Scientists with the Dawn mission believe they’re highly reflective material, likely ice. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The latest views of Ceres' enigmatic white spots are sharper and clearer, but it's obvious that Dawn will have to descend much lower before we'll see crucial details hidden in this overexposed splatter of white dots. Still, there are hints of interesting things going on here.

The latest photo is part of a sequence of images shot for navigation purposes on May 16, when the spacecraft orbited 4,500 miles (7,200 km) over the dwarf planet. Of special interest are a series of troughs or cracks in Ceres crust that appear on either side of the crater housing the spots.

While the exact nature of the spots continues to baffle scientists, Christopher Russell, principal investigator for the Dawn mission, has narrowed the possibilities: "Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice."

We've seen ice exposed by meteorite / asteroid impact before on Mars where recent impacts have exposed fresh ice below the surface long hidden by dust. In most cases the ice gradually sublimates away or covered by dust over time. But if Ceres' white spots are ice, then we can reasonably assume they must be relatively new features otherwise they would have vaporized or sublimated into space like the Martian variety.

Much has been written – including here – that these spots are the same as those photographed in much lower resolution by the Hubble Space Telescope in 2004. But according the Phil Plait, who writes the Bad Astronomy blog, that's false. He spoke to Joe Parker, who was part of the team that made the 2004 photos, and Parker says the Dawn spots and Hubble spots are not the same.

Could the spots have formed post-2004 or were they simply too small for Hubble to resolve them? That seems unlikely. The chances are slim we'd just happen to be there shortly after such a rare event occurred? And what happened to Hubble's spot – did it sublimate away?

Ceres Bright Spots Sharpen But Questions Remain
Comparison of the most recent photos of the white spots taken Dawn’s current 4,500 miles vs. 8,400 miles on May 4. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Watching the still images of Ceres during rotation, it's clear that sunlight still reflects from the spots when the crater fills with shadow at sunset and sunrise. This implies they're elevated, and as far as I can tell from the sunrise photo (see below), the brightest spots appear to shine from along the the side of a hill or mountain. Could we be seeing relatively fresh ice or salts after recent landslides related to impact or tectonic forces exposed them to view?

Let's visit another place in the solar system with an enigmatic white spot, or should I say, white arc. It's Wunda Crater on Uranus' crater-blasted moon Umbriel. The 131-mile-wide crater, situated on the moon's equator, is named for Wunda, a dark spirit in Aboriginal mythology. But on its floor is a bright feature about 6 miles (10 km) wide. We still don't know what that one is either!

  • Ceres Bright Spots Sharpen But Questions Remain
    The bright material in both photos was excavated from below the surface and deposited nearby by a 2008 impact that dug a crater about 26 feet (8 meters) in diameter. The extent of the bright patch was large enough for the Compact Reconnaissance Imaging Spectrometer for Mars, an instrument on NASA’s Mars Reconnaissance Orbiter, to obtain information confirming it as water ice. Credit: NASA/JPL-Caltech/University of Arizona
  • Ceres Bright Spots Sharpen But Questions Remain
    NASA’s Hubble Space Telescope took these images of the asteroid 1 Ceres over a 2-hour and 20-minute span, the time it takes the Texas-sized object to complete one quarter of a rotation. The observations were made in visible and in ultraviolet light. Hubble took the snapshots between December 2003 and January 2004. Credit: NASA, ESA, J. Parker, P. Thomas and L. McFadden
Video compiled from Dawn’s still frames of Ceres by Tom Ruen. Watch as the spots continue to reflect light even at local sunset.

Explore further

Ceres animation showcases bright spots

Source: Universe Today
Citation: Ceres bright spots sharpen but questions remain (2015, May 25) retrieved 25 June 2019 from https://phys.org/news/2015-05-ceres-bright-sharpen.html
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User comments

May 25, 2015
They're still insisting it's ice reflecting even though it still shines after the sunset. Belief is a powerful agent, in spite of the obvious.

May 25, 2015
They're still insisting it's ice reflecting even though it still shines after the sunset. Belief is a powerful agent, in spite of the obvious.

From the observations they shine for a very short time after sunset and before sunrise. Mountain peaks catch the light before the sun rises on the crater floor, so this is still consistent with ice (or salt) on a mountain peak.

Yet you are sure that it is something else - you even say that it is obvious. Why don't you state right here and now what you think that it so obviously is. Then if further observations show that you are wrong, lose that annoying attitude from your posts.

May 26, 2015
This comment has been removed by a moderator.

May 26, 2015
@BH - I am sorry that you found my reply to CD85 offensive.

I'm not stating an opinion that it is ice, or that it is salt - I'm pointing out that in contrast to CD85's claim, these are consistent with the data presented in the article.

I normally don't call out CD85, but he missed that the pictures show only shine briefly after sunset, missed that the article discusses this as being compatible with ice or salt on a mountain peak, and then, rather than re-reading to see what he had missed, arrogantly assumed that he knew more than than the scientists running the mission (ironically demonstrating that HIS belief is a powerful agent on HIS thinking).

(The only contributor that I 'bully' is JVK - he so consistently bullies other contributors that he deserves a dose of his own medicine. Even there I never create new insults - I merely show that his own insults apply to himself more than to those he is trying to bully with them (and that his own citations refute him).)

May 26, 2015
You fellows need to dig deeper and discover the filters NASA is using on these photos. Ceres is a dark red-brown, very low albedo in natural light. These spots are just less dark and are not "white" by any stretch.

May 26, 2015
@Shooist - Yes, Ceres has an albedo of only about 0.09, but the bright sports are several times brighter and I'd guestimate them at at least 0.4 and probably more like 0.6. But I haven't seen any actual figures on their albedo - have you found any data? Thanks.

May 26, 2015
keep up the great work: jk is on the ropes- he has resorted to appealing to people to attack us now and downvote/report any heretics which refute his posts

Not enough for you, RS, to limit your opinion to 'it's ice'. You got to go on and attack personally.

Interesting the info on mountain peaks. Dumb shit on your bullying of other contributors
it wasn't bullying
you always have the option of using "ignore" or simply not reading any of the comments

Belief is a powerful agent, in spite of the obvious.
just like belief in the grand canyon/moon crater formation even though we've observed meteor's hitting the moon, and we've never found any (not ONE) scrap of credible evidence at all supporting electric universe claims re: stated above?

perhaps you should go here and learn a little about some actual physics: http://ocw.mit.edu/index.htm

you will learn about why eu is not possible

May 26, 2015
Back in March, Chris Russell of UCLA estimated 40% upwards to 100%, and that was when the spot was just a single pixel.

So now - it's more compact than expected, I'd have thought that the albedo is probably not that far off 100%. Enceladus has albedo close to 100% so that's not impossible for ice in the solar system.


May 26, 2015
Interesting the info on mountain peaks. Dumb shit on your bullying of other contributors. -bluehigh

Cantdrive "contributes" to physorg like it was a toilet.

May 28, 2015

If the charge differential is high enough a discharge occurs. It's not that difficult to understand is it? Oh that's right you went to school when space was a vacuum. Evidence does not mean anything when a false priori has been accepted as truth. That's why cantdrive will always be a heretic to you. Your Big Bang God is omnipotent.

Ya learn real physics, its micro black holes making moon craters to hide the dark matter stupids!

That's funny barakn because you are like the floaties that make you flush twice.

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