If you're curious (or other emotions) about a vote, call or write your Representative's office and ask; they'll send you a letter explaining the reasoning. Better yet, send the letter before the vote, and you'll get both (some) influence and an explanation.
I strongly second the grandparent's point: a good Representative should not always do what his/her constituents want.
Dude, what have you been smoking? 90% of real economics think Paulson's plan is horrendous, and they are right... it's kleptocracy.
I'm fascinated to see the source of your statistic. What's a "real economic [sic]"? Are they polled?
Paulson's plan is horrendous, but that's not what came to the floor of the House. The bill that was rejected yesterday added two crucial provisions (1: the taxpayers/government taking an equity share in any banks that they bail out, allowing the taxpayers to recoup some, all, or more than all of the $700bn investment, and 2: judicial and Congressional oversight of the Treasury Secretary's actions) and one substantively-meaningless-but-fun-stick-it-to-the-CEOs-who-f*cked-up provision (the limit on golden parachutes for CEOs).
No one thinks this bill is great or even good, but most (not all) of the economists I've read or heard from in the last week agree that a) the short term loans and lines of credit that are fundamental to the day-to-day workings of the economy (primarily small businesses and small banks) are at risk if we don't do something to free up the flow of capital, b) this is the only plan that's likely to pass before January 21 in the current political environment, and c) given the political reality, passing this plan (with the improvements I noted above) is better than not passing this plan.
If a better bill is politically possible (which means bipartisan support: neither governing party, for good reason, is going to put out a rescue package of this size without substantial support from the other), that's miles better. I'm no economist, so I'm not going to try to summarize the many better options out there. Again, my favorite is Paul Krugman, but there are many others.
All that said, the main point of my comment above, re the importance and effectiveness of talking to your representatives, stands.
Besides do you really think they read the majority of mail they get?
Yes. At least an intern (which I was, once) and often a staff member will read every single letter from constituents with names and addresses, even though there are typically tens or hundreds of identical form letters.
I've been involved both in lobbying and in a Congressional (House) office (as an unpaid intern). Constituent contacts really do matter: a significant fraction of the staff's time is spent reading and distilling these letters for the Congress(wo)man. On this issue, the letters are nearly universally against the rescue package, which is the only reason Congress went against the opinions of the vast majority of economists (my favorite is Paul Krugman) to vote down this bill. If you think your voice doesn't matter to your Congressman, you're crazy, even though (s)he won't always agree.
I know this is hard to believe, but direct bribes don't work. Organizing large numbers of constituents to call/email a Congressman does often work, largely because it demonstrates that you could also organize voters to challenge the Congressman at the ballot box. (That kind of organization takes money, so if anyone wants to consider that a bribe, fine; I consider it democracy.) However, an office will get tens or hundreds of copies of the same form letter from large numbers of constituents; those identical letters count less (though not hugely less) than personally written letters or phone calls.
(As of 4 years ago, when I interned in DC, phone calls, emails, faxes, and snail-mail letters count equally, but snail-mail letters take multiple weeks to get to the DC office because of anthrax-related security. Letters from in-state but out-of-district are read but carry less weight than contacts from constituents and are unlikely to get a response; letters from out-of-state or without a name and mailing address go straight to the recycling bin.)
The research was presented in a poster at the AAS meeting. I have a copy of the poster on my desk, but it's not, to my knowledge, in a generally available place, and no paper has appeared (yet). It's a tad unusual for a press release to be put out with no accompanying published paper.
The abstract is available. However, as is typical for the AAS, the abstract has to be submitted in October for the January meeting and therefore doesn't have the actual result that's in the poster.
They're estimating the scale height of the warm ionized medium (WIM), 8000 Kelvin ionized hydrogen in the interstellar medium (ISM). The WIM is modeled as having an exponential density distribution with height, z, n(z) = n_0 e^(-|z|/h). They're measuring h. There is WIM gas above one scale height, but the density at one scale height is 1/e times the density at the midplane (z=0) and continues to fall off exponentially.
The pulsar data they downloaded from the internet largely did use big, expensive instruments—this work is a new, improved analysis of a large sample of already-published data from many sources.
They did not use the canonical space-averaged electron density for the WIM (0.03 cm-3); they used pulsars with independent distance measurements*. What's different about their work from previous estimates of the scale height of the WIM is that they did not use pulsars with any of several other distance measurement techniques that are less reliable. In particular, one of the commonly used distance measurement techniques uses absorption due to neutral hydrogen in the plane of the Milky Way. However, the neutral hydrogen (cold neutral medium, CNM) disk is considerably thinner than the WIM disk (scale height of 100–250 pc, depending upon whom you ask, versus 1000 (the old result)–1800 (their new result) pc for the WIM), so that technique only works at all well for pulsars in the plane (and is still model-dependent even then), which makes it a biased sample for measuring the height of the Milky Way's disk.
These authors also limits themselves to galactic latitudes |b| > 40 degrees, which means that they're sampling a relatively local cylinder about the Sun. Therefore, their sample isn't contaminated by spiral arms or many classical H II regions (gas ionized by hot, massive stars), which will change the result.
This result is a fairly dramatic revision of the scale height of this phase of the interstellar medium and, consequently, the weight of the medium. (In fact, it's the phase I make my living studying, so it's very important to me!) However, this does not have any bearing on the scale height of the stars (which contain 85% of the mass in the Galaxy) or the neutral hydrogen. It also doesn't change the total amount of ionized gas in the WIM. (That column density is measured very accurately by pulsar dispersion.)
The WIM is certainly not uniform throughout the Galaxy. It is a turbulent medium with varying densities, and it only fills ~20% (that number is highly uncertain, to a factor of two or more, I would say) of the volume within the 1000–1800 pc high disk. However, particularly over the path lengths the more distant pulsars sample, those local differences should be pretty well averaged out.
The discrepancy with previous work is largely due to a tremendous amount of progress in recent years measuring parallax distances to pulsars, largely using very long baseline interferometry. Distance measurements in astronomy are notoriously difficult, and improvements will continue for years to come.
* They relied only upon distance measurements determined in one of two ways: parallax (the only direct distance measurement method in astronomy, useful for relatively near pulsars—out to about 1000 pc=3000 ly, with decreasing accuracy further away) and association with globular clusters. Globular clusters contain thousands of stars that were formed at about the same time and have the same heavy element content, so their distance can be determined based on standard, well-known stellar evolution models and a color-magnitude diagram. These two distance measurements are about as accurate as a pulsar distance measurement will get in the foreseeable future, although particularly the parallax distances will continue to improve both in quantity and quality.
Among airports I've been to recently, Tucson, Phoenix, Albuquerque, Denver (a recent change from a pay service), and Kansas City all have free wi-fi. When it's a hub you're changing in, you can (to a limited extent) choose your airport.
(But never change planes in Kansas City if you can avoid it -- the gate areas are so small that you have to leave security to change planes!)
It's "Domino's" Pizza and "Domino" Sugar. Which only serves to further distinguish them.
No, that's not relevant. I can't go out and start a pizza company called "Domino Pizza" or a sugar company called "Domino's" -- the names are close enough so that they could be reasonably confused.
There are a number of other examples -- Delta Airlines and Delta Faucets comes to mind -- where the names of two non-competing companies really are identical and both trademarked. (Apple, Inc., formerly Apple Computer, and Apple Records is another example, but that's a different barrel of wax.)
Midwest Airlines is still going strong; I fly them occasionally. A few years ago, they switched their 717s and MD-80s to 'leisure destinations' to 3x2 seating (instead of 2x2), and later this year, they will have 3x2 seating available on all planes, but they'll still have something like 40 seats in 2x2 seating on every plane. All seats will still be leather.
They no longer serve meals on china, as they did until relatively recently (but before I ever flew Midwest).
Will they? Before the recent merger, Cingular refused to unlock our phones, despite numerous calls to managers. Once the contract expired, we jumped to T-Mobile, had a third party unlock the Cingular phones, and have been very happy since. T-Mobile does happily unlock subsidized phones after three months.
Has Cingular changed their tune since changing their name?
(I still will not buy an iPhone until I can use it with T-Mobile without paying AT&T. Locking an unsubsidized phone does seem pure evil.)
In addition to the lower light-gathering power, interferometers need to sample a wide range of separations between pairs of antennae. The most-separated pair of antennae (the longest baseline is the jargon) gets very small structures, but is not sensitive to larger structures. You get helped by the rotation of the Earth, which makes any given pair of antennae (which are fixed on the Earth) change their angular separation with respect to the target the array is looking at, but that only helps so much. You really need a range of separations, which means many antennae.
For example, the Very Large Array has 27 antennae. That's 351 pairs, which can be spaced differently. If you had a single dish telescope the size of the VLA (or the Earth), you'd get every angular scale at once, without having to synthesize a large aperture from all the baselines.
In practice, this aperture synthesis technique works quite well, and there's no way we're going to build a steerable single dish telescope larger than the Green Bank Telescope (100m in diameter) any time in the foreseeable future.
Or the VLBA, a 'world-sized' very long baseline interferometer. At the VLBA, they record the data from each of the ten antennae to tapes with very accurate timestamps, then combine the data later at the NRAO facility in Socorro, New Mexico.
I don't believe you're allowed to fly JFK-LAX only on the Qantas flight; the JFK service is purely to provide 1-stop service to Sydney. On the Qantas web site, you can't purchase a JFK-LAX flight. See wikipedia's cabotage page. In fact, the asinine U. S. laws prohibit foreign carriers from offering domestic U. S. service even if it's connecting through a foreign country! That is, Air Canada can't offer service between two U. S. cities connecting through Toronto even though neither leg is a U. S. domestic flight.
This reminds me of an experience my Mom had back in the 70s to get around this law. (I'm fuzzy on the details.) An Air France Concorde flew from Paris (I think) into, I believe, Washington Dulles with continuing service to Dallas. They wanted to be able to pick up passengers at Dulles so they sold the plane to an American carrier (Braniff) every time this plane landed, and Braniff technically operated the Dulles-Dallas service.
I don't know of any similar arrangement these days.
Nope, your original comment that stars get cooler and more luminous during their main sequence lifetime was correct; that is up and to the right on the H-R diagram, but not much.
The lower-left (warmer, higher luminosity) boundary of the 'main sequence' is a line called the 'zero age main sequence' -- when a protostar begins nuclear fusion in its core, it lies along the zero age main sequence. The position along the zero age main sequence is determined primarily by its mass. (More massive stars are hotter and more luminous -- up and to the left on the H-R diagram, but no normal star evolves up and to the left along the main sequence.) Through its main sequence life (~10 billion years for the Sun; shorter for more massive stars and longer for less massive stars), a star expands slightly, cools slightly, and gets slightly more luminous. This evolution accounts for the thickness of the main sequence; in a typical sample of stars, you see both relatively newly formed and older main sequence stars.
This increased luminosity is rather slow; I doubt it's significant over the last century, but it is significant over the 4.6 billion year life of the Earth and the Sun, as mdsolar mentioned above.
(When the star has converted all the hydrogen in its core into helium, it leaves the main sequence and becomes much larger, cooler, and more luminous -- a red giant.)
Who are we, then (according to your logic), to publish stories about human rights atrocities in China? We should be bowing down to oppressive regimes who want us shot for being able to do so, or at least thrown in jail for life!
But the UK isn't China. From the article:
"I think we have to take every case on its own facts," said George Freeman, vice president and assistant general counsel of The New York Times Company. "But we're dealing with a country that, while it doesn't have a First Amendment, it does have a free press, and it's our position that we ought to respect that country's laws."
Because the UK does respect and protect the free press but has some restrictions that are not present in the US, the Times thinks its appropriate to follow the UK's publication laws for UK readers, even though the British government doesn't have jurisdiction over a US paper. They're neither enabling an oppressive regime nor being unreasonably absolutist.
I'm an astronomer, and my department and the laptop selection at conferences are both roughly a 50/50 split between Macs and Linux. (There were essentially no Macs about 5 years ago, before the advent of OS X. Some astronomers use Windows for PowerPoint, but very rarely for actual work -- most of the software we use is *nix-based.)
I don't think Macs have much of a foothold in the life sciences (about which I know very little), but they're quite popular in the physical sciences.
Dark matter is required by looking at galaxy rotation curves. Essentially, the rotation speed of galaxies is too fast given the mass that can be seen, so there must be some mass that doesn't emit light as conventional, baryonic matter does. Dark matter was first hypothesized by Zwicky in 1933 and has been well accepted throughout the astronomical community for decades.
Dark energy is required by looking at Type 1a supernovae from the early universe. Astronomers and cosmologists use Type 1a supernovae, which have a well known intrinsic brightness (they are called a "standard candle"), to establish a cosmological distance scale and measure the expansion rate of the universe. If the universe is composed of ordinary matter and dark matter, the self-gravity of all the matter in the universe would cause the expansion rate to slow over time. A goal of these observations was to determine whether there is enough matter in the universe to stop it from expanding forever and ultimately cause it to collapse back on itself in a "big crunch."
In about 1998, the supernova observations were pinned down well enough to show that the expansion rate is actually increasing with time. Therefore, there must be some "antigravity" force that causes the expansion of the universe to accelerate. This is dubbed "dark energy."
The "cosmic energy budget" says that about 4% of the mass/energy in the universe is ordinary matter, 23% is dark matter, and 73% is dark energy. The matter and dark matter total mass is measured from observations of the cosmic microwave background.
All of this is pretty well supported by the best current observational evidence, although the physical nature of dark matter and dark energy are both poorly understood (and new observations can always change things, of course).
The new claim in the current article is that the effect of dark energy has changed over time. The fundamental problem is that the new evidence relies on gamma-ray bursts, which are not nearly as well established a standard candle as the Type 1a supernovae, so it's much harder to say with certainty what distance they are at. Note that the new claim was presented at the American Astronomical Society meeting in DC last week; it has not yet appeared in a refereed journal. (Nature news is merely reporting on the AAS presentation.) The author himself has an appropriate degree of skepticism of his claim.
(Yes, I am an astronomy grad student, although I don't do any work on cosmology.)
Mr. Frist also voted "no" in the end, but in a purely parliamentary maneuver to allow him to try to bring up the bill again.
Thus, the final Senate vote was 52 yea, 47 nay (60 yea votes needed for cloture), with 42 of 45 Democrats and the independent but only 4 of 55 Republicans opposing the act.
Senator Russ Feingold (D-WI) was the only Senator to vote against the Patriot Act the first time around and rallied the opposition this time. Senator Feingold spent the week blogging on the floor fight at TPM Cafe.
B1508+55 is a massive radio emitting object which is boldly going into the intergalactic space where all that putative dark matter is supposed to be. If its path bends we might end up discovering a "dark galaxy".
Indeed, pulsars are used to probe the interstellar medium to get at how much mass is tied up in ionized hydrogen, which scatters incident radio waves, causing scintillation which can be observed with a radio telescope. (Scintillation is the same effect the Earth's atmosphere has on visible light from stars, known as twinkling.) One of the ways we estimate the electron density in interstellar space is by comparing the dispersion of the pulsar signal to the distance to the pulsar. (This assumes you can get an accurate measurement of the distance, which is hard and uncertain for all but the most nearby pulsars.) There aren't great constraints on how much mass is tied up in interstellar gas, although it's not a terribly hot prospect for the missing baryonic mass.
There are about 40 known pulsars that are substantially above the plane of the milky way (galactic altitude > 3 kpc or 9000 light years; this pulsar is 2.4 kpc away, according to the paper, for an altitude of 1.9 kpc). Most of these are in globular clusters or the Large and Small Magellenic Clouds, two small, nearby galaxies that orbit the Milky Way. What's remarkable about this pulsar is that it formed in the galactic plane and was kicked up that high.
Pulsars typically move at velocities of ~100 - 500 km/s, so they cover a lot of space quickly, which lets you see the changes in the scintillation pattern on solar system size scales over the course of a few months. If you want to look at big scales, you look at many different lines of sight (i.e. many different pulsars).
(Yes, I am a pulsar/interstellar medium astronomer, or at least a grad student who works in this area and knows very little.);)
I worked in a US Rep's DC office until a few months ago. Hand written mail counts exactly the same as paper mail, but snail mail takes 2-4 weeks to get to the office because it's opened and scanned at a site in Pennsylvania (or something) before it comes near Washington. If you want to send paper mail, send it to the district office (which doesn't have the same security precautions as the DC office), but it really is no different than email.
Personally written mail (electronic or paper) is worth more than a form letter, of course.
Mail not from constituents goes to the recycle bin without being read.
Phone calls are worth more (particularly psychologically -- if the interns are overwhelmed dealing with the calls, you make an impression). Stopping by the district or DC office to politely and respectfully discuss the issue is worth the most. A constituent will essentially always get a brief hearing with a staffer.
It varies a bit by office, of course, but this is generally true.
I can see justification for a use tax for things like motor vehicles because the state has to pay to repair the roads etc., but I see no justification for a use tax for things like a PDA or a history book.
Huh? Taxes aren't usage fees, they're essentially the only way the government has to raise money to pay for the social services they provide. Should the government charge you every time you utilize the education system or the police force? Of course not. Therefore, they have to assess taxes on something else, and the general sales tax is the primary source that state governments use. It's the cost of living in a civil society.
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If you're curious (or other emotions) about a vote, call or write your Representative's office and ask; they'll send you a letter explaining the reasoning. Better yet, send the letter before the vote, and you'll get both (some) influence and an explanation.
I strongly second the grandparent's point: a good Representative should not always do what his/her constituents want.
Dude, what have you been smoking? 90% of real economics think Paulson's plan is horrendous, and they are right... it's kleptocracy.
I'm fascinated to see the source of your statistic. What's a "real economic [sic]"? Are they polled?
Paulson's plan is horrendous, but that's not what came to the floor of the House. The bill that was rejected yesterday added two crucial provisions (1: the taxpayers/government taking an equity share in any banks that they bail out, allowing the taxpayers to recoup some, all, or more than all of the $700bn investment, and 2: judicial and Congressional oversight of the Treasury Secretary's actions) and one substantively-meaningless-but-fun-stick-it-to-the-CEOs-who-f*cked-up provision (the limit on golden parachutes for CEOs).
No one thinks this bill is great or even good, but most (not all) of the economists I've read or heard from in the last week agree that a) the short term loans and lines of credit that are fundamental to the day-to-day workings of the economy (primarily small businesses and small banks) are at risk if we don't do something to free up the flow of capital, b) this is the only plan that's likely to pass before January 21 in the current political environment, and c) given the political reality, passing this plan (with the improvements I noted above) is better than not passing this plan.
If a better bill is politically possible (which means bipartisan support: neither governing party, for good reason, is going to put out a rescue package of this size without substantial support from the other), that's miles better. I'm no economist, so I'm not going to try to summarize the many better options out there. Again, my favorite is Paul Krugman, but there are many others.
All that said, the main point of my comment above, re the importance and effectiveness of talking to your representatives, stands.
Besides do you really think they read the majority of mail they get?
Yes. At least an intern (which I was, once) and often a staff member will read every single letter from constituents with names and addresses, even though there are typically tens or hundreds of identical form letters.
I've been involved both in lobbying and in a Congressional (House) office (as an unpaid intern). Constituent contacts really do matter: a significant fraction of the staff's time is spent reading and distilling these letters for the Congress(wo)man. On this issue, the letters are nearly universally against the rescue package, which is the only reason Congress went against the opinions of the vast majority of economists (my favorite is Paul Krugman) to vote down this bill. If you think your voice doesn't matter to your Congressman, you're crazy, even though (s)he won't always agree.
I know this is hard to believe, but direct bribes don't work. Organizing large numbers of constituents to call/email a Congressman does often work, largely because it demonstrates that you could also organize voters to challenge the Congressman at the ballot box. (That kind of organization takes money, so if anyone wants to consider that a bribe, fine; I consider it democracy.) However, an office will get tens or hundreds of copies of the same form letter from large numbers of constituents; those identical letters count less (though not hugely less) than personally written letters or phone calls.
(As of 4 years ago, when I interned in DC, phone calls, emails, faxes, and snail-mail letters count equally, but snail-mail letters take multiple weeks to get to the DC office because of anthrax-related security. Letters from in-state but out-of-district are read but carry less weight than contacts from constituents and are unlikely to get a response; letters from out-of-state or without a name and mailing address go straight to the recycling bin.)
The research was presented in a poster at the AAS meeting. I have a copy of the poster on my desk, but it's not, to my knowledge, in a generally available place, and no paper has appeared (yet). It's a tad unusual for a press release to be put out with no accompanying published paper.
The abstract is available. However, as is typical for the AAS, the abstract has to be submitted in October for the January meeting and therefore doesn't have the actual result that's in the poster.
They're estimating the scale height of the warm ionized medium (WIM), 8000 Kelvin ionized hydrogen in the interstellar medium (ISM). The WIM is modeled as having an exponential density distribution with height, z, n(z) = n_0 e^(-|z|/h). They're measuring h. There is WIM gas above one scale height, but the density at one scale height is 1/e times the density at the midplane (z=0) and continues to fall off exponentially.
The pulsar data they downloaded from the internet largely did use big, expensive instruments—this work is a new, improved analysis of a large sample of already-published data from many sources.
They did not use the canonical space-averaged electron density for the WIM (0.03 cm-3); they used pulsars with independent distance measurements*. What's different about their work from previous estimates of the scale height of the WIM is that they did not use pulsars with any of several other distance measurement techniques that are less reliable. In particular, one of the commonly used distance measurement techniques uses absorption due to neutral hydrogen in the plane of the Milky Way. However, the neutral hydrogen (cold neutral medium, CNM) disk is considerably thinner than the WIM disk (scale height of 100–250 pc, depending upon whom you ask, versus 1000 (the old result)–1800 (their new result) pc for the WIM), so that technique only works at all well for pulsars in the plane (and is still model-dependent even then), which makes it a biased sample for measuring the height of the Milky Way's disk.
These authors also limits themselves to galactic latitudes |b| > 40 degrees, which means that they're sampling a relatively local cylinder about the Sun. Therefore, their sample isn't contaminated by spiral arms or many classical H II regions (gas ionized by hot, massive stars), which will change the result.
This result is a fairly dramatic revision of the scale height of this phase of the interstellar medium and, consequently, the weight of the medium. (In fact, it's the phase I make my living studying, so it's very important to me!) However, this does not have any bearing on the scale height of the stars (which contain 85% of the mass in the Galaxy) or the neutral hydrogen. It also doesn't change the total amount of ionized gas in the WIM. (That column density is measured very accurately by pulsar dispersion.)
The WIM is certainly not uniform throughout the Galaxy. It is a turbulent medium with varying densities, and it only fills ~20% (that number is highly uncertain, to a factor of two or more, I would say) of the volume within the 1000–1800 pc high disk. However, particularly over the path lengths the more distant pulsars sample, those local differences should be pretty well averaged out.
The discrepancy with previous work is largely due to a tremendous amount of progress in recent years measuring parallax distances to pulsars, largely using very long baseline interferometry. Distance measurements in astronomy are notoriously difficult, and improvements will continue for years to come.
* They relied only upon distance measurements determined in one of two ways: parallax (the only direct distance measurement method in astronomy, useful for relatively near pulsars—out to about 1000 pc=3000 ly, with decreasing accuracy further away) and association with globular clusters. Globular clusters contain thousands of stars that were formed at about the same time and have the same heavy element content, so their distance can be determined based on standard, well-known stellar evolution models and a color-magnitude diagram. These two distance measurements are about as accurate as a pulsar distance measurement will get in the foreseeable future, although particularly the parallax distances will continue to improve both in quantity and quality.
Among airports I've been to recently, Tucson, Phoenix, Albuquerque, Denver (a recent change from a pay service), and Kansas City all have free wi-fi. When it's a hub you're changing in, you can (to a limited extent) choose your airport.
(But never change planes in Kansas City if you can avoid it -- the gate areas are so small that you have to leave security to change planes!)
No, that's not relevant. I can't go out and start a pizza company called "Domino Pizza" or a sugar company called "Domino's" -- the names are close enough so that they could be reasonably confused.
There are a number of other examples -- Delta Airlines and Delta Faucets comes to mind -- where the names of two non-competing companies really are identical and both trademarked. (Apple, Inc., formerly Apple Computer, and Apple Records is another example, but that's a different barrel of wax.)
Midwest Airlines is still going strong; I fly them occasionally. A few years ago, they switched their 717s and MD-80s to 'leisure destinations' to 3x2 seating (instead of 2x2), and later this year, they will have 3x2 seating available on all planes, but they'll still have something like 40 seats in 2x2 seating on every plane. All seats will still be leather.
They no longer serve meals on china, as they did until relatively recently (but before I ever flew Midwest).
Will they? Before the recent merger, Cingular refused to unlock our phones, despite numerous calls to managers. Once the contract expired, we jumped to T-Mobile, had a third party unlock the Cingular phones, and have been very happy since. T-Mobile does happily unlock subsidized phones after three months.
Has Cingular changed their tune since changing their name?
(I still will not buy an iPhone until I can use it with T-Mobile without paying AT&T. Locking an unsubsidized phone does seem pure evil.)
In addition to the lower light-gathering power, interferometers need to sample a wide range of separations between pairs of antennae. The most-separated pair of antennae (the longest baseline is the jargon) gets very small structures, but is not sensitive to larger structures. You get helped by the rotation of the Earth, which makes any given pair of antennae (which are fixed on the Earth) change their angular separation with respect to the target the array is looking at, but that only helps so much. You really need a range of separations, which means many antennae.
For example, the Very Large Array has 27 antennae. That's 351 pairs, which can be spaced differently. If you had a single dish telescope the size of the VLA (or the Earth), you'd get every angular scale at once, without having to synthesize a large aperture from all the baselines.
In practice, this aperture synthesis technique works quite well, and there's no way we're going to build a steerable single dish telescope larger than the Green Bank Telescope (100m in diameter) any time in the foreseeable future.
Or the VLBA, a 'world-sized' very long baseline interferometer. At the VLBA, they record the data from each of the ten antennae to tapes with very accurate timestamps, then combine the data later at the NRAO facility in Socorro, New Mexico.
I don't believe you're allowed to fly JFK-LAX only on the Qantas flight; the JFK service is purely to provide 1-stop service to Sydney. On the Qantas web site, you can't purchase a JFK-LAX flight. See wikipedia's cabotage page. In fact, the asinine U. S. laws prohibit foreign carriers from offering domestic U. S. service even if it's connecting through a foreign country! That is, Air Canada can't offer service between two U. S. cities connecting through Toronto even though neither leg is a U. S. domestic flight.
This reminds me of an experience my Mom had back in the 70s to get around this law. (I'm fuzzy on the details.) An Air France Concorde flew from Paris (I think) into, I believe, Washington Dulles with continuing service to Dallas. They wanted to be able to pick up passengers at Dulles so they sold the plane to an American carrier (Braniff) every time this plane landed, and Braniff technically operated the Dulles-Dallas service.
I don't know of any similar arrangement these days.
Nope, your original comment that stars get cooler and more luminous during their main sequence lifetime was correct; that is up and to the right on the H-R diagram, but not much.
The lower-left (warmer, higher luminosity) boundary of the 'main sequence' is a line called the 'zero age main sequence' -- when a protostar begins nuclear fusion in its core, it lies along the zero age main sequence. The position along the zero age main sequence is determined primarily by its mass. (More massive stars are hotter and more luminous -- up and to the left on the H-R diagram, but no normal star evolves up and to the left along the main sequence.) Through its main sequence life (~10 billion years for the Sun; shorter for more massive stars and longer for less massive stars), a star expands slightly, cools slightly, and gets slightly more luminous. This evolution accounts for the thickness of the main sequence; in a typical sample of stars, you see both relatively newly formed and older main sequence stars.
This increased luminosity is rather slow; I doubt it's significant over the last century, but it is significant over the 4.6 billion year life of the Earth and the Sun, as mdsolar mentioned above.
(When the star has converted all the hydrogen in its core into helium, it leaves the main sequence and becomes much larger, cooler, and more luminous -- a red giant.)
But the UK isn't China. From the article:
Because the UK does respect and protect the free press but has some restrictions that are not present in the US, the Times thinks its appropriate to follow the UK's publication laws for UK readers, even though the British government doesn't have jurisdiction over a US paper. They're neither enabling an oppressive regime nor being unreasonably absolutist.
Very large paychecks for whom? Astronomers? Hah! I'm an astronomer, so please let me know where those can be found.
(If you're in astronomy for the money, you're crazy.)
I'm an astronomer, and my department and the laptop selection at conferences are both roughly a 50/50 split between Macs and Linux. (There were essentially no Macs about 5 years ago, before the advent of OS X. Some astronomers use Windows for PowerPoint, but very rarely for actual work -- most of the software we use is *nix-based.)
I don't think Macs have much of a foothold in the life sciences (about which I know very little), but they're quite popular in the physical sciences.
Misspelling "sentence" makes the 1 +/- 1 sentence summary even better.
Dark matter is required by looking at galaxy rotation curves. Essentially, the rotation speed of galaxies is too fast given the mass that can be seen, so there must be some mass that doesn't emit light as conventional, baryonic matter does. Dark matter was first hypothesized by Zwicky in 1933 and has been well accepted throughout the astronomical community for decades.
Dark energy is required by looking at Type 1a supernovae from the early universe. Astronomers and cosmologists use Type 1a supernovae, which have a well known intrinsic brightness (they are called a "standard candle"), to establish a cosmological distance scale and measure the expansion rate of the universe. If the universe is composed of ordinary matter and dark matter, the self-gravity of all the matter in the universe would cause the expansion rate to slow over time. A goal of these observations was to determine whether there is enough matter in the universe to stop it from expanding forever and ultimately cause it to collapse back on itself in a "big crunch."
In about 1998, the supernova observations were pinned down well enough to show that the expansion rate is actually increasing with time. Therefore, there must be some "antigravity" force that causes the expansion of the universe to accelerate. This is dubbed "dark energy."
The "cosmic energy budget" says that about 4% of the mass/energy in the universe is ordinary matter, 23% is dark matter, and 73% is dark energy. The matter and dark matter total mass is measured from observations of the cosmic microwave background.
All of this is pretty well supported by the best current observational evidence, although the physical nature of dark matter and dark energy are both poorly understood (and new observations can always change things, of course).
The new claim in the current article is that the effect of dark energy has changed over time. The fundamental problem is that the new evidence relies on gamma-ray bursts, which are not nearly as well established a standard candle as the Type 1a supernovae, so it's much harder to say with certainty what distance they are at. Note that the new claim was presented at the American Astronomical Society meeting in DC last week; it has not yet appeared in a refereed journal. (Nature news is merely reporting on the AAS presentation.) The author himself has an appropriate degree of skepticism of his claim.
(Yes, I am an astronomy grad student, although I don't do any work on cosmology.)
Senator Russ Feingold (D-WI) was the only Senator to vote against the Patriot Act the first time around and rallied the opposition this time. Senator Feingold spent the week blogging on the floor fight at TPM Cafe.
Indeed, pulsars are used to probe the interstellar medium to get at how much mass is tied up in ionized hydrogen, which scatters incident radio waves, causing scintillation which can be observed with a radio telescope. (Scintillation is the same effect the Earth's atmosphere has on visible light from stars, known as twinkling.) One of the ways we estimate the electron density in interstellar space is by comparing the dispersion of the pulsar signal to the distance to the pulsar. (This assumes you can get an accurate measurement of the distance, which is hard and uncertain for all but the most nearby pulsars.) There aren't great constraints on how much mass is tied up in interstellar gas, although it's not a terribly hot prospect for the missing baryonic mass.
There are about 40 known pulsars that are substantially above the plane of the milky way (galactic altitude > 3 kpc or 9000 light years; this pulsar is 2.4 kpc away, according to the paper, for an altitude of 1.9 kpc). Most of these are in globular clusters or the Large and Small Magellenic Clouds, two small, nearby galaxies that orbit the Milky Way. What's remarkable about this pulsar is that it formed in the galactic plane and was kicked up that high.
Pulsars typically move at velocities of ~100 - 500 km/s, so they cover a lot of space quickly, which lets you see the changes in the scintillation pattern on solar system size scales over the course of a few months. If you want to look at big scales, you look at many different lines of sight (i.e. many different pulsars).
(Yes, I am a pulsar/interstellar medium astronomer, or at least a grad student who works in this area and knows very little.) ;)
Um, this isn't an editorial; it's an op-ed piece by Times columnist Nicholas Kristof.
I worked in a US Rep's DC office until a few months ago. Hand written mail counts exactly the same as paper mail, but snail mail takes 2-4 weeks to get to the office because it's opened and scanned at a site in Pennsylvania (or something) before it comes near Washington. If you want to send paper mail, send it to the district office (which doesn't have the same security precautions as the DC office), but it really is no different than email.
Personally written mail (electronic or paper) is worth more than a form letter, of course.
Mail not from constituents goes to the recycle bin without being read.
Phone calls are worth more (particularly psychologically -- if the interns are overwhelmed dealing with the calls, you make an impression). Stopping by the district or DC office to politely and respectfully discuss the issue is worth the most. A constituent will essentially always get a brief hearing with a staffer.
It varies a bit by office, of course, but this is generally true.