Volcanoes on Venus ?

The European Space Agency has an interesting news release about some new mapping data from its Venus Express spacecraft:

Venus Express has charted the first map of Venus’ southern hemisphere at infrared wavelengths. The new map hints that our neighbouring world may once have been more Earth-like, with a plate tectonics system and an ocean of water.

The fact that the instruments operate at infrared wavelengths makes it possible for them to “see” thorough the cloud layer that covers Venus. The map is built up from over 1,000 images taken from May 2006 to December 2007.

Earlier Russian spacecraft, which landed on the planet’s surface, touched down in relatively low-lying areas, and found rock basically similar to basalt, an igneous rock.  The infrared mapping includes some higher plateaus, and is capable of giving some information on the chemical composition of the surface rock, based on its emissivity in the infrared portion of the spectrum.   The rocks on the plateaus appear “lighter” than those in the lower-lying areas.  On Earth, this kind of difference usually means that one is looking at granite, rather than basalt.  And the presence of granite has implications for the history of the area:

Granite is formed when ancient rocks, made of basalt, are driven down into the planet by shifting continents, a process known as plate tectonics. The water combines with the basalt to form granite and the mixture is reborn through volcanic eruptions.

If the inference that the lighter rock is granite is correct, it suggests that Venus may at one time have had plate tectonics similar to those on Earth.   One interpretation is that the higher “plateaus” were once continents, surrounded by seas of water:

The new data are consistent with suspicions that the highland plateaus of Venus are ancient continents, once surrounded by ocean and produced by past volcanic activity.

“This is not proof, but it is consistent. All we can really say at the moment is that the plateau rocks look different from elsewhere,” says Nils Müller at the Joint Planetary Interior Physics Research Group of the University Münster and DLR Berlin, who headed the mapping efforts.

The mapping instruments did not detect any really large temperature differences, as might be seen after recent volcanic activity, but they did find “darker” areas, which might be the remnants of past lava flows.

Venus, as a planet similar in size to the Earth, is still something of an enigma, but the new data will perhaps provide some more clues to why it evolved so differently from the Earth.

Firefox 3.5 Vulnerability

Brian Krebs at the Washington Post is reporting, in his “Security Fix” blog, a newly-discovered vulnerability in the recently released Firefox 3.5 browser.  The problem is apparently connected with the new implementation of JavaScript that was introduced with version 3.5.   There is no fix available at the moment, but there is a workaround, described in Brian’s article, that should disable the affected component.  (Although I trust Brian’s work, I have not yet been able to independently confirm this.)  See update below

To set up the workaround, type into the address bar (where you would usually enter a URL) the string:

        about:config

Note there are no spaces.  You will then get a slightly tongue-in-cheek dialog box that says “This might void your warranty”.  Click on the button that says “I’ll be careful, I promise!”.  This will bring up a very long list of options, with a search box at the top of the list.  Type the string ‘jit’ into the search box; you should then have the list narrowed down to two options.  Locate the line that looks like this:

 javascript.options.jit.content ...    true

After you double-click the line, the value should change from true to false. That’s all that’s required.  You may notice some slowdown in performance on JavaScript-intensive sites, such as Google Docs or Facebook.

Users who have the NoScript extension installed should also be protected on sites where the extension disables JavaScript;  however, since so many sites today require JavaScript to function, this protection may not be all that valuable.

I’ve been running with the workaround in place for a couple of hours, and haven’t seen any real problems so far.

Update, Tuesday, July 14, 16:40

The existence of the problem, and the temporary workaround, have now been confirmed by an entry on the Mozilla Security Blog.  A more permanent fix is in the works.

Microsoft Security Bulletin, July 2009

Microsoft today released its usual monthly “Black Tuesday: set of security updates.  According to the Security Bulletin, there are three updates for components of Microsoft Windows, all rated Critical, and one update for the Publisher component of Microsoft Office, rated Important.  The final two updates, both rated Important, are for Microsoft’s ISA server, and for its Virtual PC / Virtual server products.  The three Windows vulnerabilities apply to all supported versions of WIndows.

The Security Bulletin, mentioned earlier, has links to download the fixes, in the section “Affected Software and Download Locations”.  These fixes should also be made available via the normal Windows Update mechanism.

Since the Windows vulnerabilities are rated Critical, and since at least one of them is being actively exploited, I recommend installing the fixes as soon as possible.

The SANS Institute has their usual monthly overview of the updates.