3550 posts • joined Wednesday 28th February 2007 21:13 GMT
More likely they're down to the interior of the Moon contracting as it has cooled.
The range on the ages of these features is pretty wide; they're anywhere from 1.2 Gya to 50 Mya years ago (most probably towards the younger end of the scale). Lunar geologists have an especially broad definition of 'recent' - even compared to terrestrial geologists.
That there was much going on on the Moon after 1 Gya is interesting enough; the youngest feature with a firm(ish) date is the Compton–Belkovich thorium anomaly, a patch of highly evolved silicic rock on the lunar far side which has been estimated at 800 Mya - 1 Gya.
It'd be interesting to see if any of the glowing Transient Lunar Phenomena which are occasionally reported by astronomers can be tied to these faults. One of the explanations for TLPs is that gas might still be coming out of the interior of the Moon.
Re: Very cool...
'Does the moon still have a hot core? Is there anyway to find out (from earth)? Probably not unless one observed some sort of Luna volcano??'
The exact state of the Moon's core is uncertain. Apollo left a series of ALSEPs packages on the surface to record heat flow from the interior and register impacts which could have revealed the structure of the interior. In their period of operation we found out the heat flow is very low, but nothing big enough to send a good shock through the core hit the Moon before the instruments were turned off. Having said that, some top notch seismic boffinry has been done on the Moon.
The best estimate is that the lunar core is tiny - no more than 350km across. It's probably nickel-iron alloy with sulfur and silicon like the Earth's core. It is suggested there is a solid or mostly solid inner core about half the diameter of the whole core. The outer core is probably liquid but not convecting violently like the Earth's (hence no appreciable lunar magnetic field), but this is somewhat disputed.
Over that is the mantle which is divided into two, a lower zone about 500km in diameter which appears to be either partially molten or highly plastic and might contain sizeable pockets of magma. The outer mantle is relatively cold, solid and appears not to contain any sizeable amounts of magma.
There has been some mathematical and laboratory modelling of the lunar interior by VU University Amsterdam which used the European Synchrotron Radiation Facility to examine the behaviour of postulated lunar magma under very high temperatures and pressures. Their discovery is that the titanium-rich magmas responsible for forming the rocks returned by Apollo and Luna are unlikely to be able to rise through the lunar mantle because they are denser than the warm mantle. However, if the mantle continues to cool and become denser, we could see a resumption of vulcanism on the Moon.
Seems very optimistic to design, prototype and build a new reactor design by 2020. Especially one with sodium cooling which has never been trouble-free in the past. Good luck to them, but I wouldn't be putting money on seeing the big red switch (there is a big red switch isn't there?) being pressed in eight years' time.
So if Blunkett, Clarke, Blears and the very lovely Meg Hillier had had their way we'd have now been talking about scrapping tens of thousands of them. If only they'd been told in advance this wasn't going to work...
....oh, in news just breaking - they were.
Re: "systems from GPS to TV rely on satellites"
Junk is a problem in geostationary orbit. So far no collisions have occurred, but that has been through foresight.
Gravitational perturbations from the Sun and Moon mean that satellites don't remain on station. All geosynchronous satellites require regular 'station keeping' burns to keep them more or less in place. After they have been abandoned they can wander significantly away from where we thought they are and since comms sats are clustered over the most advantageous positions, that is a serious risk. Operators are now required to demonstrate that their satellites can be fired into a graveyard orbit a few hundred km further away from Earth at the end of their lives.
I think this can only be properly visualised using the medium of Playmobil.
Perhaps the Catholic Church would be less objectionable if it followed the National Trust and sold more tea towels?
Probably need to be a Russian rocket. ExoMars was going to use a pair of Atlas Vs. A couple of Protons might be able to do the same job.
But yes, let's throw ExoMars open to the Russians, Chinese, Indians, Japanese and anyone else who wants to explore Mars.
That'll be the three downloads or fewer service then.
Apollo far side mission
Apollo 17's Harrison Schmidt proposed an Apollo mission to the lunar far side with a landing site in the crater Tsiolkovskiy. It would have used a TIROS satellite orbiting around L2 to talk back to Earth.
It never went much beyond a 'what if?' and the budget cuts to Apollo doomed it.
Silly nuclear explosions?
SILLY NUCLEAR EXPLOSIONS?
I was 8 - watching that much stuff blow up was precisely what I wanted to see. I don't want a big black box I want stuff blowing up.
Space 1999's first episode might go a long way to explaining my choice of chemistry...
You're forgetting the 1st Law of Andersonian physics
Does it look cool?
The Eagles look incredibly cool - therefore everything else goes by the wayside.
I'd really hope they'd remake it with models - 'Moon' a couple of years ago looked so much more real (and not too dissimilar from Space 1999) because they used whacking great models rather than pixels.
The 2nd Law of Andersonian physics is that stuff blows up - regularly. Even stuff that shouldn't blow up. This is a good thing. Unless you're near the stuff blowing up.
The Atlantic is a mature ocean, sooner or later it will begin to see subduction occurring around its margins (currently really only happening in the Caribbean margin, in South Sandwich and possibly getting started off Portugal.
If that happens, the UK might one day have some lovely volcanoes whose effect on house prices will really upset the Daily Mail.
The Urals are a suture between two former continents when the former Siberian plate collided with Pangaea, so yep it is perfectly correct for geologists consider them to mark a continental divide as the geology on either side is so profoundly different.
But then, you could claim the same for most of Scotland and North Wales which are geologically much more similar to Greenland than they are to London.
The only really new bit in this work is the possible location of the new supercontinent (and it's a pretty safe bet none of us will be around to prove otherwise). That the Atlantic was widening, the Pacific floor being subducted and Africa and India burrowing into the belly of Eurasia is Geology 101. But the animations are nice.
So long as you are in the US
You are afforded the protection of the Constitution whether you are a citizen or no. Outside the US - then that's asking for a cruise missiling.
That I grant you, but can I nominate second place?
It has to be the first shot of the Earth Moon system which was captured by Voyager 1 from over 7 million miles out.
BTW if you've never seen them, the Earthrise images sent back by the Soviet Zond 7 probe (an unmanned trial of a possible manned lunar mission) are quite beautiful:
Mars 6 and Mars 7 - same problem
Both probes were effectively dead on arrival at Mars because of radiation damage to their microprocessors. Mars 6 deployed its lander but it died before it could reach the Martian surface - some data about the atmosphere's composition was returned however. Mars 7 ejected its lander too early for the same reason, both the lander and the orbital module went into orbit around the Sun.
What's shocking is that this happened in 1973.
In 1988 and 1989 respectively, the two Fobos probes were lost because of software issues.
With the above
I'm glad someone told me who that was in the photo, she looks nothing like Rachel Weisz - more like a monochrome muppet out of 'Avatar'.
Directions to Robin Hood airport
(Taken from Robin Hood: Prince of Thieves)
Start from Dover, drive north, keep driving north, turn south at Hadrian's Wall, take the 'Noddinhum' exit, third forest on the right.
Who'd have thought it
Too dumb to be allowed into LA.
You're not thinking big enough
Plutonium 239 produces 2W/kg in decay heat. A few hundred kilos of that should keep you nice and toasty and put an end to any problems with the neighbours just as soon as you declare yourself an independent nuclear state.
There are 87 tons of the stuff in the UK right now - we should be parcelling it up to help old people stay warm this winter.
I have so many good ideas.
'Remember it's not that long since scientists told us we were heading for a new ice age. They are now telling us that theory was wrong then so I don't propose to blindly trust them now.'
No they weren't - this is a myth.
It was only ever a small minority of climate scientists who thought the Earth was due to enter a period of cooling before the onset of another glacial episode. A short lived period of relative cooling in the 1970s wasn't well understood, but there was a theory that interglacials (such as the one we're going through) lasted about 10k years, and we were about 10k years into the Holocene interglacial - so the only way for temperatures to go was down and this might be the first sign of a new glacial advance. We now know that there is no such thing as a fixed length interglacial - they are much more irregular and tend to be much longer lived - this has now been resolved thanks to deep ice cores. We are now also much more aware how local cooling in the Pacific ocean can bring about cooler weather conditions across the globe over a period of years.
The majority of scientists were already warning that carbon emissions were forcing temperatures higher. There was no year from 1965 onwards where cooling predictions were more common than warming ones and they pretty much all stopped by 1977. The best summary of the research at the time:
Peterson, Thomas C.; William M. Connolley, and John Fleck (2008). "The Myth of the 1970s Global Cooling Scientific Consensus". Bulletin of the American Meteorological Society 89 (9): 1325–1337
The televisual deep throat also let on the mind-blowing factoid that Apple was going to release something that was 'very thin'.
Here's my stab-in-the-dark prediction for which I'm dropping the usual consultancy fee - it will also be very shiny.
'How much extra power would it take to dump the space garbage on the moon?'
To go to the Moon from the ISS, you'd have to accelerate from c. 7kms-1 low Earth orbit velocity to c. 11kms-1 in order to achieve escape velocity. So the short answer is: 'a lot'.
There are also complexities about choosing when you can go as the ISS's orbit is inclined with respect to that of the Earth-Moon system.
It's not an assumption, it's a fact. Not only did Apollo bring back pieces of meteorite in their samples, but impacts have actually been observed:
(and many more).
On Earth you can use shocked quartz to identify impact sites, but there's precious little quartz in lunar rocks.
Can you answer an advanced theological question?
Where do tealights fit into all this? The useless bloody things cast no useful amount of light or heat but appear to be needed by the skip load in order to achieve full domestic harmony.
It'll mean the all-British Daily Express will be able to reclaim pole position for purveyor of weird conspiracy theories and epic idiocy masquerading as news.
The early Cambrian must have been like some sort of ITV game show 'tonight only one family will be going through into the Ordovician, the others will be turned into coal. We asked 100 trilobites...'
Superficially it has some similarities to Crinoids which pop up in the Ordovician and were largely extinctified in the Permian. But this is a bilaterally symmetric beastie whereas crinoids (like other echinoderms) have five-fold symmetry.
The fossils in the article are amazing. I'd love to have one - but not quite as much as I'd like a tyrannosaur in the living room...
Mars probes and microprocessors
The Russians really haven't had much luck with microchips to Mars. Both Mars 6 and Mars 7 returned huge amounts of garbage when they finally reached the planet because solar radiation had eaten their microprocessors.
Not that the software was much better; Fobos 1 received an untested software patch that resulted in it losing lock on the Sun and being unable to charge its batteries. Fobos 2's computer failed, but IIRC it was never determined if the error was hardware or software.
Mars is the only candidate for the various shergottites, nakhlites and chassignites that have been found.
Unlike almost all other meteorites (with the exception of the lunar meteorites) they don't date to 4.6Gya, they have been radio dated to between 1.3Gya and 0.18Gya implying they came from a planet that was geologically active until relatively recently.
Their mineralogy which is generally magic to ultramafic - similar to that of the Earth's Mantle, again suggesting their origin was a planet that has differentiated.
Gas trapped in glass inclusions in the shergottites have the exact isotopic ratios as that returned from Martian probes.
Finally, some of the meteorites contain minerals that are only formed by weather in wet conditions.
In short, Mars is the only candidate.
upgrading family cooking stoves (what, my Kenmore?)
You're off the hook - they're worried about people who have to burn wood, dung or kerosene in stoves or for lighting and heat. Most stoves in the developing world haven't changed in the last few thousand years and are very inefficient. They produce huge amounts of tiny particles that cause long term health problems. Producing a more efficient stove (of which plenty of simple, appropriate designs that can be built in the community that use them already exists) would help solve this problem, it would free up people's time as they would need to gather less fuel, improve their financial situation if they have to buy fuel and it would be good for the environment if fewer trees were hacked down for firewood.
If only we could do the same for the bloody goats that people think make great charity gifts when in fact they help desertification.
With any luck some of m'learned friends will soon be paid spectacularly well to do just that.
The US legal system, unlike DVDs, is multi region.
Not just because of physics, but nickel + hydrogen under very high pressures is a staple part of modern chemistry for making everything from margarine to hydrogenating coal. If copper was a result - even in very small quantities - it would poison the catalyst and this would have been recorded in the chemistry texts.
Not copying Ambilight is hardly surprising because as you say, it's patented to buggery (excuse my legalese), but it is odd that no one else in the telly market has experimented with 21:9 screens.
Sounds a bit like Fon
The Fon network from Fonera has a similar principle for WiFi. Fon charges a one-time fee for a small WiFi router. If you then choose to share some of your bandwidth (how much is up to you) with the public, you get free access to all other public Fon hotspots anywhere in the world. Of which there are a lot. The company also runs a revenue sharing model where you can get a share of any fees paid by people who buy a pass when they try to connect to your router.
When do you want him?
Obviously we'd be heart-broken to lose such a popular and charismatic minister, well known for his ideology-free, consensual approach; but perhaps it would be for the best if one more toxic reptile made its home in Australia.
The LEAF comes with a solar panel on the back spoiler as an optional extra. But that only gives 10W - just enough juice to charge the auxiliary 12V battery which powers the onboard computers and the lighting.
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