This is not about Carbon dating at all (that's about looking at the decay of Carbon 14, produced by cosmic ray radiation high in the atmosphere), this is about the Carbon 12/13 isotope ratio used as an indicator of biological activity in the distant past. Basically, what they say they found was that this is only trustworthy in deep ocean sediments, not on land or in island sediments, and you can only find deep ocean sediments for the last 150 million years or so, due to plate tectonics recycling the sea floor.
This will not affect geological dating at all. It may affect the interpretation of some work regarding, e.g., extinction events. It's hard to say without looking in detail at the other work (they may have several lines of evidence, etc.).
Since the Reagan era, we don't reveal all of the orbits of everything we launch. It's not, of course, like the Russians don't know the orbits of these other satellites, but they are not in our lists.
And, any observation net can only track objects down to a certain size, probably in the few ounce range for 13,000 objects.
Yes, but in astronomy virtual telescope generally means a computer compilation of various sky surveys, so you can type in a coordinate and see what is there. This is totally different, VLBI provides a real telescopic view, just synthesized by interferometry.
As an analogy, Google Earth is a virtual spy satellite. An orbiting synthetic aperture radar is a real spy satellite, just with a synthesized image.
If you had an array of Hubble sized telescopes in space and could put them whatever distance you'd like from each other, what sort of results could you get?
That is basically the Space Interferometry Mission (SIM), which alas has had funding troubles recently. The component telescopes are not the size of the Hubble, but the idea is exactly as you suggest. One thing you could do with this is detect Earth sized planets in a solar system like ours out to a reasonable distance.
There is an accretion disk around the event horizon, where things (dust, gas) are orbiting around at nearly the speed of light. As these things rub together, and as new stuff gets added, there is lots of energy to be detected far away - especially in jets of very hot matter out of the poles.
The event horizon itself, for a black hole of this size, is not detectable. (Very small black holes should glow with Hawking radiation.)
General relativity makes no predictions about what is happening at the center of black holes - there is a singularity in the equations there. Worse, in general relativity singularities are (probably) never "naked" - if you go in to see what is happening you can never come back out, or send a signal back out, to tell us about it.
But, yet, the gravity of the black hole, as experienced outside, does increase with time as things get sucked in.
Gee, after 40 frigging years of VLBI you think people would have some clue about aperture synthesis. It ain't no virtual telescope, it's just as real as any other, it's just that the images are done after the fact.
Depends on the error ellipse of the orbit determination for the junk, and it sounds like the uncertainty is a good fraction of a mile in size. But in any case, the miss distance is a mile after the course adjustment, not before.
What makes them (or you) think that alien life will have any DNA at all?
The Earth and Mars have been exchanging biological material all along, through meteor impacts. To me, that makes it highly likely that there is a biosystem there, and fairly likely that there is some commonality between the two biosystems.
(Of course, the dynamical arguments are interesting, and may even give a high probability, but to prove it IMHO we will have to send a spacecraft there. Don't hold your breath.)
Sedna is supposed to have resulted from an interaction between the Oort cloud and a distant passage of another Star in the past. That means that there is a good chance (30% or so) that it belonged to the OTHER stars Oort cloud.
2006 SQ372 has an even more irregular orbit which is unstable to boot. The same sort of arguments will apply to this object, and so there is a decent chance that it, too, will prove to come from another solar system.
Slashdot Mirror
He's a cool guy, but I wonder where this is going.
Note that the paper is only about carbon dating of shelf sediments, *not* fossils.
No, it is about the carbon cycle, not carbon dating. The word dating does not appear in this article.
This is not about Carbon dating at all (that's about looking at the decay of Carbon 14, produced by cosmic ray radiation high in the atmosphere), this is about the Carbon 12/13 isotope ratio used as an indicator of biological activity in the distant past. Basically, what they say they found was that this is only trustworthy in deep ocean sediments, not on land or in island sediments, and you can only find deep ocean sediments for the last 150 million years or so, due to plate tectonics recycling the sea floor.
This will not affect geological dating at all. It may affect the interpretation of some work regarding, e.g., extinction events. It's hard to say without looking in detail at the other work (they may have several lines of evidence, etc.).
The British newspaper The Independent started a campaign to save Betchley Park on 20 August 2008. I wonder if these are connected ?
Sounds like a great cause - it should definitely be preserved.
By the way, the asteroid is 2867 Steins. (The numbers are generally included with the name.)
And text to go with the images.
Here are the first results. The asteroid has a nice crater chain on it and looks roughly like a cut diamond.
All of those were British shows first.
Since the Reagan era, we don't reveal all of the orbits of everything we launch. It's not, of course, like the Russians don't know the orbits of these other satellites, but they are not in our lists.
And, any observation net can only track objects down to a certain size, probably in the few ounce range for 13,000 objects.
Yes, but in astronomy virtual telescope generally means a computer compilation of various sky surveys, so you can type in a coordinate and see what is there. This is totally different, VLBI provides a real telescopic view, just synthesized by interferometry.
As an analogy, Google Earth is a virtual spy satellite. An orbiting synthetic aperture radar is a real spy satellite, just with a synthesized image.
If you had an array of Hubble sized telescopes in space and could put them whatever distance you'd like from each other, what sort of results could you get?
That is basically the Space Interferometry Mission (SIM), which alas has had funding troubles recently. The component telescopes are not the size of the Hubble, but the idea is exactly as you suggest. One thing you could do with this is detect Earth sized planets in a solar system like ours out to a reasonable distance.
There is an accretion disk around the event horizon, where things (dust, gas) are orbiting around at nearly the speed of light. As these things rub together, and as new stuff gets added, there is lots of energy to be detected far away - especially in jets of very hot matter out of the poles.
The event horizon itself, for a black hole of this size, is not detectable. (Very small black holes should glow with Hawking radiation.)
General relativity makes no predictions about what is happening at the center of black holes - there is a singularity in the equations there. Worse, in general relativity singularities are (probably) never "naked" - if you go in to see what is happening you can never come back out, or send a signal back out, to tell us about it.
But, yet, the gravity of the black hole, as experienced outside, does increase with time as things get sucked in.
Gee, after 40 frigging years of VLBI you think people would have some clue about aperture synthesis. It ain't no virtual telescope, it's just as real as any other, it's just that the images are done after the fact.
According to that list, there are 12 objects with a probability >1/10,000, and 2 with a probability > 1/1000.
Note that the uncertainty on these orbits is frequently many 1000's of km; the orbits of things in LEO are much better determined.
Depends on the error ellipse of the orbit determination for the junk, and it sounds like the uncertainty is a good fraction of a mile in size. But in any case, the miss distance is a mile after the course adjustment, not before.
And this article about The Bank Account that Sprang a Leak
about sums up why. My accounts, too, have sprung leaks in the past...
About sums it up.
I took the new math, took lots of algebra along with the set theory, and actually thought it helped me as a physicist.
Lots depends on what you want to do. I can't imagine not knowing calculus, but plenty of people don't and they somehow don't seem to miss it.
This was common knowledge when I was taking advanced Math classes in mid 1970's.
What makes them (or you) think that alien life will have any DNA at all?
The Earth and Mars have been exchanging biological material all along, through meteor impacts. To me, that makes it highly likely that there is a biosystem there, and fairly likely that there is some commonality between the two biosystems.
Who really cares, except for some people trying to make money consulting and vending on this topic ?
Once we (or, more likely, our machines) do go there, isotope analysis will make it pretty clear whether it comes from this solar system or not.
Go there.
(Of course, the dynamical arguments are interesting, and may even give a high probability, but to prove it IMHO we will have to send a spacecraft there. Don't hold your breath.)
Sedna is supposed to have resulted from an interaction between the Oort cloud and a distant passage of another Star in the past. That means that there is a good chance (30% or so) that it belonged to the OTHER stars Oort cloud.
2006 SQ372 has an even more irregular orbit which is unstable to boot. The same sort of arguments will apply to this object, and so there is a decent chance that it, too, will prove to come from another solar system.