VLBI is 51 years old (it actually started in the late 1960's) but it is high quality eVLBI that is basically a product of our century (made possible by all of that nice optical fiber criss-crossing our planet).
It's a pity few even realize what a problem light pollution is.
Indeed. Galileo made many of his observations from the city of Venice. Back then, you could still see the stars from a city center. Now, even the outer suburbs are pretty degraded.
This is called eVLBI, and it is now done routinely to, e.g., determine the Earth's rotation (UT1).
From a networking standpoint, one interesting thing is that eVLBI requires high bandwidth (1 Gbps is typical), but can tolerate fairly high loss rates (because the actual cross correlation coefficients are rarely as high as 10^-3). This makes it an excellent candidate for an Internet scavenger service, where packets are sent at "less than best effort," i.e., with the understanding that they can be dropped if there is any congestion at all, so that eVLBI can use all available bandwidth without choking out other uses. The same technology may prove to be very useful for P2P services.
I haven't received any memo. Tell us how they have solved the radiation problem.
Various groups are working on this. The radiation is largely charged particles, and so can be defected by magnetic fields. This British group was in the news about this 2 years ago and it seems to work well.
A shielded safe room would also be a good idea, for really extreme events. I thought that the ISS has one, but I cannot find a reference. SOHO and Stereo should be able to give adequate warning.
The Apollo missions were short duration, and during Solar Minimum, but they were taking a chance. There was a risk (which was known at the time) that a major solar flare could kill the astronauts while they were in cis-lunar space.
Of course, this was not the only risk they faced...
If you are going to do truly long duration flights (where you have to grow your own food) you also have to worry about replacing things, like clothes, o-rings, cables, etc. If you could bioengineer silkworms to provide some of this (well, of course the clothes might as well be silk, so you may be done there), then you would really help make long-duration flight sustainable.
Is anyone who pas attention really surprised by this ? (Except for the people who get paid to make other people scared about things, like Attorneys General.)
That is true, but I was actually referring to people applying for visas in non-visa waiver countries. People apply months in advance and are left in limbo, receive the visa well after the dates of travel, etc. And, visa's may be approved for one trip, never arrive for the next, and then come promptly for later travel. Actual visa denials, by contrast, appear to be quite rare, at least for professionals traveling on business. It seems very capricious to an outsider.
I am involved with this professionally, and the complaints have risen a level where international scientific meetings planned for the USA are being rescheduled elsewhere.
I run a business, and I wouldn't do this, nor would I put up with it.
My teachers, by the way, certainly did not do this. Back when I was going to school the velvet dictatorship was not so entrenched.
It is sad how easily a people slip from free to not-free. You will likely complain about how unfair that judgement is; time will tell which judgement is correct.
I honestly think of the U.K. as a former democracy. The forms are there, but they don't actually seem to mean anything and the state does whatever it wants. (Oh, there are protest marches, but they seem to be as irrelevant as Garry Kasparov protesting outside the Kremlin.)
We are about to find out whether that is also true in the USA.
Heck, I traveled a lot in the 1970's. Went to the USSR, went to Yugoslavia, Japan, India, etc. Never had to give fingerprints and (at least for the Common Market), the process was pretty painless.
People used to make jokes about the USSR because of the difficulty and arbitrariness of their visa process. Just saying...
For my contract at a school district in Pennsylvania I had to do a child abuse background check (Which had to be mailed in with a $10 money order, no personal checks), a $10 State Police background check, and $40 to have my prints put on file with the FBI/checked with the FBI via the local intermediate unit. It's widely required at other places of employment, as well.
"You" (i.e., the foreign national) never had any rights to begin with. Just ask anyone who has had to get a US visa in the last 8 years (if not more). They rarely turn them down, the visa just never appears (which has the same effect, of course). And, there is no reason given and no appeal.
Really, it's the cosmologists. If it is not hydrogen or helium, it's a metal. I am not really sure why - maybe because there is a fair amount of lithium, and that is a metal.
This convention is not used by, say, the astronomers who deal with extra-solar system planets.
Well, the point is that in cosmology or extra-galactic astronomy, almost everything visible is almost entirely Hydrogen or Helium. The sloppy convention is to call the little bit left over "metals," although I know people who call it "dust," depending on the circumstances. Carbon (say) is definitely not a metal, but it would be called that in cosmology. It's just a convention.
Slashdot Mirror
Good catch.
VLBI is 41 years old.
(Sorry, too little coffee early in the AM.)
VLBI is 51 years old (it actually started in the late 1960's) but it is high quality eVLBI that is basically a product of our century (made possible by all of that nice optical fiber criss-crossing our planet).
It's a pity few even realize what a problem light pollution is.
Indeed. Galileo made many of his observations from the city of Venice. Back then, you could still see the stars from a city center. Now, even the outer suburbs are pretty degraded.
If you care about changing this (and a lot can be done), join the International Dark-Sky Association.
This is called eVLBI, and it is now done routinely to, e.g., determine the Earth's rotation (UT1).
From a networking standpoint, one interesting thing is that eVLBI requires high bandwidth (1 Gbps is typical), but can tolerate fairly high loss rates (because the actual cross correlation coefficients are rarely as high as 10^-3). This makes it an excellent candidate for an Internet scavenger service, where packets are sent at "less than best effort," i.e., with the understanding that they can be dropped if there is any congestion at all, so that eVLBI can use all available bandwidth without choking out other uses. The same technology may prove to be very useful for P2P services.
I haven't received any memo. Tell us how they have solved the radiation problem.
Various groups are working on this. The radiation is largely charged particles, and so can be defected by magnetic fields. This British group was in the news about this 2 years ago and it seems to work well.
A shielded safe room would also be a good idea, for really extreme events. I thought that the ISS has one, but I cannot find a reference. SOHO and Stereo should be able to give adequate warning.
There has been work on a artificial magnetosphere as most of the damaging radiation in deep space is actually charged particles, not gamma rays.
There will also need to be a "safe room" in case of a solar flare. I believe that the ISS has one of these.
The Apollo missions were short duration, and during Solar Minimum, but they were taking a chance. There was a risk (which was known at the time) that a major solar flare could kill the astronauts while they were in cis-lunar space.
Of course, this was not the only risk they faced...
If you are going to do truly long duration flights (where you have to grow your own food) you also have to worry about replacing things, like clothes, o-rings, cables, etc. If you could bioengineer silkworms to provide some of this (well, of course the clothes might as well be silk, so you may be done there), then you would really help make long-duration flight sustainable.
That's not what I hear.
Is anyone who pas attention really surprised by this ? (Except for the people who get paid to make other people scared about things, like Attorneys General.)
That is true, but I was actually referring to people applying for visas in non-visa waiver countries. People apply months in advance and are left in limbo, receive the visa well after the dates of travel, etc. And, visa's may be approved for one trip, never arrive for the next, and then come promptly for later travel. Actual visa denials, by contrast, appear to be quite rare, at least for professionals traveling on business. It seems very capricious to an outsider.
I am involved with this professionally, and the complaints have risen a level where international scientific meetings planned for the USA are being rescheduled elsewhere.
I run a business, and I wouldn't do this, nor would I put up with it.
My teachers, by the way, certainly did not do this. Back when I was going to school the velvet dictatorship was not so entrenched.
It is sad how easily a people slip from free to not-free. You will likely complain about how unfair that judgement is; time will tell which judgement is correct.
Where's that spirit in the mother country?
I honestly think of the U.K. as a former democracy. The forms are there, but they don't actually seem to mean anything and the state does whatever it wants. (Oh, there are protest marches, but they seem to be as irrelevant as Garry Kasparov protesting outside the Kremlin.)
We are about to find out whether that is also true in the USA.
Heck, I traveled a lot in the 1970's. Went to the USSR, went to Yugoslavia, Japan, India, etc. Never had to give fingerprints and (at least for the Common Market), the process was pretty painless.
People used to make jokes about the USSR because of the difficulty and arbitrariness of their visa process. Just saying...
For my contract at a school district in Pennsylvania I had to do a child abuse background check (Which had to be mailed in with a $10 money order, no personal checks), a $10 State Police background check, and $40 to have my prints put on file with the FBI/checked with the FBI via the local intermediate unit. It's widely required at other places of employment, as well.
And you did this ?
"You" (i.e., the foreign national) never had any rights to begin with. Just ask anyone who has had to get a US visa in the last 8 years (if not more). They rarely turn them down, the visa just never appears (which has the same effect, of course). And, there is no reason given and no appeal.
This is a visa under a different name
I always feel I am fighting it to get it to do what I want. If I wanted to fight computers, I would buy computer games.
Pigs will fly over the frozen landscape of hell well before Airforce One is built by a non-American company.
They don't even serve French wines in the White House; no way are they going to buy a plane made in France.
(And yes, I know that Airbus buys US components. Doesn't matter.)
I would also point out that these papers did not detect anything like filaments or braids.
The EU is wrong on so many levels that IMHO it is not even interesting. I. E. Segal's ideas were at least interesting.
Lithium is almost entirely produced in the Big Bang.
I think that that is where it came from. And, it is sloppy because they are not (all) metals.
Maybe because Lithium (a real metal) was also produced in the Big Bang :
http://astro.berkeley.edu/~mwhite/darkmatter/bbn.html
Really, it's the cosmologists. If it is not hydrogen or helium, it's a metal. I am not really sure why - maybe because there is a fair amount of lithium, and that is a metal.
This convention is not used by, say, the astronomers who deal with extra-solar system planets.
Well, the point is that in cosmology or extra-galactic astronomy, almost everything visible is almost entirely Hydrogen or Helium. The sloppy convention is to call the little bit left over "metals," although I know people who call it "dust," depending on the circumstances. Carbon (say) is definitely not a metal, but it would be called that in cosmology. It's just a convention.
To astronomers, Everything that's not hydrogen or helium, is a metal.
(Chemists have different viewpoints.)