It was part of research into climate change over the past 1000 years. The oxygen isotopes in carbonates in clam shells provide information about climate at the time the shell layer was formed. See: http://www.bangor.ac.uk/news/full.php.en?nid=16781&tnid=0

True. I think their presentation of things is more the result of current publishing demands: useful or even innovative is not good enough anymore to get your paper through, it needs to be "new" and "never done before" instead of an innovation on an existing technique.

Still, I find the complete lack of any reference to even the words "track & stack" weird, given that tracking & stacking is common practise in imaging faint asteroids. Maybe not when you use a 5-meter telescope, but with with smaller instruments it is often done. I have used the technique myself o faint asteroids and much-used astrometry packages like Astrometrica have a standard option for it.

Small addition: the technique is called "track & stack" when employed on moving objects. Most existing astrometric software can do it.

The more sensitive camera and the algorithm to empirically find the correct direction and speed of movement of a not-known asteroid are new.

The method of overlaying multiple short images so that the asteroid is a pinpoint additive composite of multiple images and the stars become trails is not new.

The latter technique is called "stacking" (a word existing for quite a long time and meaning the same as their "synthetic tracking"). It is regularly done to image and get astrometry on faint objects, when speed and direction of movement are already known (e.g. in follow-up observations on a Near earth Asteroid that already has some observations over the previous hours/days and hence a preliminary orbit). That part is really not new, and there is no need to invent new terminology ("synthetic tracking") for it.

Frankly, it is weird that the authors nowhere mention "stacking" as an existing technique that is often used in imaging faint asteroids. It suggests they did not investigate whether their "new" technique is really that new. Yes, they innovate on it, but they did not invent a completely novel technique.

A number of asteroids have moons (most well known pair: (243) Ida and Dactyl). So moons are clearly not restricted to planets.

Pleistocene Park, not Pliocene Park.

The Plio-Pleistocene boundary is at 2.6 million years ago. With 700 000 yrs, this Horse is Middle Pleistocene (the Lower-Middle Pleistocene boundar is at 780 000 yrs ago).

There is no such consensus at all.

For the bow and arrow: yes. For throwing spears: no.

The 350 000 yrs old Schöningen (Germany) wooden spears, which predate Homo sapiens, are finally balanced with the center of balance at 1/3rd of their length. They have the balance and shape of an Olympic throwing javelin. Experiments with replica's show they are indeed quite suited as throwing spears.

The weak point of this new study is that it actually does not differentiate impact marks from thrusting from impact marks from throwing. It merely assumes that traces of a stone tip equate a throwing spear. And in placing the earliest evidence in an early H. sapiens context in S-Africa, it overlooks evidence elsewhere in a non-sapiens context.

Neandertals in Eurasia for example did haft stone points to pieces of wood: we know this because stone points with remnants of birch tar have been found (e.g. at Campanello, Italy). There is also the find of a wild ass vertebra from Um el Tlel in Syria with a Levallois stone point deeply embedded in it. In addition: a throwing spear does not have to be stone-tipped.

There is a disparity between their summary table (which lists 4803) and the full table of orbital elements of all Apollo's they (the MPC) provide. The latter counts 5203 objects

Yay, what a surprise: "likely an Apollo"...[sarcasm] gosh, that is unexpected! [/sarcasm]

Given that the vast majority of objects in earth-crossing orbits are Apollos, that is hardly a surprising conclusion. It would have been much more interesting if it was an Aten - much less of those around. Or a comet fragment

87% of asteroids in earth-crossing orbits are Apollos. 13% are Atens. Then there is a n unknown quantity of cometary objects

That SNC meteorites are from Mars was a main stream notion in meteoritics already well before the ALH 84001 "fossil" announcement. It was NOT with the ALH 84001 announcement that that link was first made. The first suggestions date from 1979. For ALH 84001 it is somewhat different: it initially had been misidentified as a diogenite (because its composition is mostly low-Ca pyroxene) and was found to be a SNC-related meteorite in 1994 (two years before the ALH 84001 "fossil" announcement). Its oxygen isotope fractionation is very similar to SNC's.

True, there are a few scientific dissenters about a Martian origin for SNC meteorites but they are few. Their main problem is to explain what the parent body of these meteorites is if it is not Mars. It needs to be a large differentiated body with active volcanism in the past, volcanism still active less than 1 billion yrs ago (which points to a body of planetary size). It needs to have posessed an atmosphere quite similar in noble gas composition as that measured on Mars by the Viking probes, and another clue is the similar chemical composition of the Mars surface and these meteorites. The Oxygen Isotopes moreover show that this parent body cannot be the earth-moon system, and they also differ in this from HED meteorites (linked to Vesta), as do their "young" crystalization ages.

The idea that scientists worldwide would engage in a 'conspiracy' just to save the face of a US President is ridiculous by the way. Many scientists studying ALH 84001 and other Martian meteorites are not even American - we foreign scientists don't give a rats arse about the reputation of your former President!

The controversy about ALH 84001 was not that it is from Mars (that is pretty much agreed upon): the controversy was about nanofossils purportedly discovered in this meteorite.

The problem is to recognize them: Mars and Moon meteorites stand out in the lab by their composition. Earth meteorites just look like, well, any common stone on the earth surface. So an analysis will say: "nope, it is just a terrestrial rock, not a meteorite".

A fresh fallen one will have a fusion crust, but it might be dismissed a a weathering crust.

The OTP ought to cut severely in the hyperbole. There is very little (read: no) "bad news" in all of this. Most of what is brought up is FUD aimed at fooling people to think the North Koreans "failed" again (as crazy commies should). Truth is: this time they didn't.

1) Tumbling does not increase the changes of a collision at all. It is completely irrelevant for the collision danger whether a satellite tumbles or not;

2) Tumbling does not really influence the orbit (only in the final stages of decay it does). Indeed, it is completely unclear what is meant by a "stable orbit" here. ALL satellite orbits decay over time, so NONE of them is "stable". Probably, it is meant to imply that the Korean satellite has no reboosting capability. That is probably part of the design (many simpler satellites have no reboosting capability).

Yes, maybe the Koreans have no control over the attitude of the object. But that doesn't matter much: nothwithstanding Korean claims of it being a "weather satellite" this was probably never meant to be a truely functioning satellite.

The fact is that the North Koreans managed to successfully bring an object into earth orbit this time, and that in itself is an achievement. Whether you like them or not (and I don't like the North Koreans), those are the facts. No amount of spin and hyperbole about "danger" and "bad news" can take away that fact. This is all simply FUD.

With the current rate of decay and solar flux, the A & B object will decay about 2-3 months from now.

They are in completely different orbits: so no.