Unexpected detail in first-ever Venus south pole images
http://www.esa.int/SPECIALS/Venus_Express/SEMUTYNFGLE_0.html
Good stuff. Kudos to the team for successful operations and a quick first release.
I'm curious as to the wavelengths in the dayside image. It's probably stretched beyond "human" RGB to show that much detail, but it would be fantastic to have a multispectral dataset and sate some curiosity about what a "true" color spacecraft image of Venus would look like. VEx will answer this question as well as one could expect.
The IR nightside makes me wonder about the prospects of seeing the surface through the cloud layers. That's a whole lot of cloud signal. Maybe greater temporal coverage will show us the surface in peeks here and there. Also, other IR may show the surface signal better.
I'm surprised how the UV image looks -- quite different from the Pioneer images. Lots of calibration questions.
Anyone here smart enough to work out the lat/lon gridlines for these first images? Presumably a half decent astronomy programme would at least tell where the subsolar point was on Venus @ say 9:07 UT on the 11th..
Well, since the axial inclination is only 3 degrees, you can count on the apparent pole always being pretty close to the actual pole. There's only one real degree of freedom in the subsolar point.
UV map seems to show surface details, but this should be only my impression (atmosphere should be more transparent in IR and visible features do not match with radar maps around south pole...).
The deepsest features visible are estimated at 55 km above the Venusian surface.Thats according to ESA website.
UV shouldn't ever show surface detail, I don't think. The clouds reflect UV and absorb it, but shouldn't let very much pass through. There is an unknown UV absorber that "marks" some clouds and leaves others unaffected.
IR will not show the surface at many wavelengths of IR. The temperature of Venus produces an IR glow in many wavelengths, and CO2 absorbs it at others. It is not so neat a situation as at Titan.
Nope, UV NEVER punches through to the surface -- but some limited near-IR spectral bands do, and Galileo's near-IR maps of Venus in those wavelengths during its flyby provided a temperature map that matched up beautifully with radar maps of Venus' surface topography. Venus Express' far more detailed and sensitive surface temperature maps should be able to reveal any small regions of current surface volcanism. The real question is whether they will be able to pierce the cloud interference enough to also provide at least a little data on surface composition near the north pole (or at least a distinction between granitic and basaltic rocks).
Even if the atmosphere were cloud-free I suspect that the extreme rayleigh scattering of UV light and the immense thickness of the atmosphere alone would preclude the possibility of imaging any detail. Here's an image of the CN tower which has been ruined by UV dispersion.
I got some more info out of Kevin Baines about these images...
http://www.planetary.org/news/2006/0414_First_Venus_Express_VIRTIS_Images_Peel.html
--Emily
Not at all -- no radar on this one. However, VIRTIS WILL be able to provide a good deal of entirely new and important surface information -- which, combined with its atmospheric science, is why it's the single most important instrument on the craft.
Unfortunately, the currently-stuck PFS is the second most important; and it's important for the two instruments to make their atmospheric observations simultaneously. For this reason, I imagine they will put in considerable effort -- and even be willing to run some risks -- to unstick it.
I was not aware of Planet Fourier Spectometer (PFS) that is stuck now. What was the problem?
An extract from ESA's portal on Venus Express
PFS will be able to measure the temperature of the atmosphere between altitudes of 55–100 kilometres at a very high resolution. It will also be able to measure the surface temperature and therefore be able to search for volcanic activity. In addition to its temperature measurements, PFS will be able to make composition measurements of the atmosphere.
Will the PFS be able to deduct the surface contour according to its temperature? I don't believe it as a reliable indicator since the surface might have different refraction/absorption properties of light/heat.
Did anyone catch the Venus Express TV Special on Science channel?
I was surprised how fast it went to air.
At the end of the ep you see the images released so far.
It interesting to see the discussion of life and whats it's really like on the surface.
http://news.bbc.co.uk/1/hi/sci/tech/6041570.stm
Scientists at the Division of Planetary Sciences meeting in Pasadena, California, this week said that data streaming from the Venus Express probe had provided unprecedented detail of the Venusian atmosphere and the first-ever peek at its lower strata.
Well - stuff should start hitting the PDS soon....we need a slinted-type effort to process the whole damn lot in an easily viewable option.
Doug
A new press release for VEX but just two images !
http://www.esa.int/SPECIALS/Venus_Express/SEM65OV74TE_0.html
Two more images and one more movie have dribbled out:
http://www.esa.int/esaSC/SEMCTD0CYTE_index_0.html
Sigh. I'd give a lot to see them just release a daily or even weekly apoapsis image so we could watch the clouds move....I'm really not asking for anything fancy...
--Emily
Well it's a fairly boring mission from my point of view. We'll never land on Venus anyway. I've just put Venus Express on ignore since ESA doesn't seem to want to keep updates flowing regularly. Much more exciting stuff at Saturn and Mars. Where we might, one day, conceivably land a human.
Anyone see the recent Sky at Night special on Venus Express? They only showed a couple of pictures, and they were all from the ESA website and ones we've already seen. And come to think of it, they didn't really say much at all about Venus Express science, certainly didn't reveal anything new.
Yup - I was watching very closely.....did you spot the Victoria crater navcam pan.....anyho - very very little actually about VEX.....but to be honest, that's what I've come to expect from VEX - they had the platform to say "we're seing this this and this" - and said almost nothing.
Doug
http://www.esa.int/esaCP/SEM4KXPJNVE_index_0.html
In case ustrax wasn't clear, there is a new release showing surface details resolved by VIRTIS.
I wonder, could any of you folks who like playing with simulated views of the planets produce a better Magellan comparison image than the one ESA released? They used a horrible base map. The comparison should be a global view centered at 270 E, 27 S, according to the caption information.
--Emily
Nice write-up about this on your blog, Emily. However, I think that the release image shows both the actual data from VIRTIS, as well as a simulated view of temperatures based on altimetry data from Magellan, not VIRTIS data corrected for altitude. so this release is more about showing how well surface temperatures correlate with altitude.
Yes, the Magellan map is modelled temperature based on topography and some assumed lapse rate. The key here is to look for differences between measured and modelled temps, which might reveal hot spots - active volcanism.
And Emily - your map of the Venus hemisphere is - alas - wrong! You are looking at Ovda Regio, not Phoebe. You're about 180 degrees off. Mixed up east and west longitudes?
Phil
The trick will be to minimize interference from variable cloud opacity and any specrtral color imparted to the surface emitted near IR filtering up through the clouds by varying cloud properties. The more data the accumulate, the more they will be able to cherry-pick data with the lowest cloud interference. For precise searches for thermal hotspots, they'll have to convolve the surface emissions with the blur-function of the atmosphere, and then the blur-and-sampling of the Venus Express observations before decisively detecting a thermal anomaly.
The VIRTIS map from ESA is labelled with negative longitudes, with -90 at center. If you just enter 90 without noticing the sign you get your 180 shift. Curse the backwards rotation of Venus!
Phil
"... Curse the backwards rotation of Venus!"
I'm having fun thinking of worse.. how about a planet with an IMAGINARY rotation. (sqrt(-1))
We apparently have small riged-body asteroids with 2 spin axes, I think Toutatis is one. Does a tumbling spin, like an American Football.
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