Highway to the Vapor Cone
February 16, 2016 8:48 AM Subscribe
Ensign John Gay of the U.S. Navy had just returned home from several months aboard the U.S.S. Constellation in the South Pacific when his phone rang. A reporter for a photography magazine was on the line, hoping to discuss the 2000 World Press Photo Awards. Gay was perplexed: “Who are you and what do you want?” he said. The reporter explained that Gay’s photo had taken first prize in the Science and Technology category, which was news to Gay: he didn’t even know he’d entered the prestigious contest.
A+ thread title.
posted by Evstar at 9:02 AM on February 16, 2016 [22 favorites]
posted by Evstar at 9:02 AM on February 16, 2016 [22 favorites]
That picture looks like it'd be from a pro-abstinence sex ed video directed by Michael Bay.
posted by Riki tiki at 9:03 AM on February 16, 2016 [3 favorites]
posted by Riki tiki at 9:03 AM on February 16, 2016 [3 favorites]
The article first said he was using a "digital SLR" and then says he had to develop the film?
posted by Evstar at 9:06 AM on February 16, 2016
posted by Evstar at 9:06 AM on February 16, 2016
Fans of F1 are familiar with this phenomena, vapor trails form on the spoilers in the right conditions.
posted by OHenryPacey at 9:09 AM on February 16, 2016 [3 favorites]
posted by OHenryPacey at 9:09 AM on February 16, 2016 [3 favorites]
If this were a still from a Michael Bay film the jet would be emerging from a fireball.
posted by The Card Cheat at 9:11 AM on February 16, 2016 [1 favorite]
posted by The Card Cheat at 9:11 AM on February 16, 2016 [1 favorite]
2000, probably NOT using a DSLR.
posted by evilDoug at 9:18 AM on February 16, 2016 [3 favorites]
posted by evilDoug at 9:18 AM on February 16, 2016 [3 favorites]
Huh. I KNOW that the caption on the photo in the very article described it as "breaking the sound barrier", but when I went back to copy/paste it, the caption had been changed to the correct "An F/A-18 Hornet over the Pacific Ocean, in July 1999."
posted by yhbc at 9:25 AM on February 16, 2016
posted by yhbc at 9:25 AM on February 16, 2016
The article first said he was using a "digital SLR" and then says he had to develop the film?
I asked the editor of Atlas Obscura about this on Twitter and she's checking into it.
Yhbc, somebody pointed the caption issue on Twitter to her as well, so presumably she fixed it.
posted by Horace Rumpole at 9:30 AM on February 16, 2016
I asked the editor of Atlas Obscura about this on Twitter and she's checking into it.
Yhbc, somebody pointed the caption issue on Twitter to her as well, so presumably she fixed it.
posted by Horace Rumpole at 9:30 AM on February 16, 2016
Some people (and Adobe Lightroom) anachronisitally use develop for analogous processes in digital photography. And a friend of the family had a Nikon D1 in 2001 -2002 so I'm guess they were available. But knowing what a D1 cost in 2002, I'm guessing a dSLR retail price at the beginning of Gay's deployment was close to 1/5 to 1/3 of an ensign's post tax take home pay.
Maybe it was USN property but signed out semi permanently to Gay...
posted by midmarch snowman at 9:47 AM on February 16, 2016
Maybe it was USN property but signed out semi permanently to Gay...
posted by midmarch snowman at 9:47 AM on February 16, 2016
The article first said he was using a "digital SLR" and then says he had to develop the film?
I'm thinking its because nobody really ever used the term "film SLR" it was just SLR and now if you told somebody you were using an SLR they would just think you meant a Digital SLR because film is now in the land of stamps and handsom cabs. Also I noticed that he "scanned" in the pictures to send them out.
posted by Pembquist at 10:01 AM on February 16, 2016
I'm thinking its because nobody really ever used the term "film SLR" it was just SLR and now if you told somebody you were using an SLR they would just think you meant a Digital SLR because film is now in the land of stamps and handsom cabs. Also I noticed that he "scanned" in the pictures to send them out.
posted by Pembquist at 10:01 AM on February 16, 2016
The article's explanation seems to be overly nitpicky in the service of coming up with a "contrarian" description of the photograph. Those regions of vapor *are* areas where the flow is locally supersonic (see the linked NASA publication, which is excellent and also nice to look at even if you don't follow the particulars) and the aircraft is traveling at least close to the speed of sound.
The patterns you see in F1 (or, say, off the edge of a flap on a commercial jet) aren't due to supersonic flow, they're not moving fast enough, so if I had to hazard a guess, I'd say that you're seeing a pressure rise.
posted by indubitable at 10:27 AM on February 16, 2016
The patterns you see in F1 (or, say, off the edge of a flap on a commercial jet) aren't due to supersonic flow, they're not moving fast enough, so if I had to hazard a guess, I'd say that you're seeing a pressure rise.
posted by indubitable at 10:27 AM on February 16, 2016
Hey, I wrote the caption for this picture when it first appeared in Sports Illustrated. (SI submitted the photo to the World Press Photo contest.) Of course, I was only going by the info my photo editor supplied, soi don't blame me for getting the science wrong. (Blame my fact-checker!)
posted by stargell at 10:37 AM on February 16, 2016 [23 favorites]
posted by stargell at 10:37 AM on February 16, 2016 [23 favorites]
I can't speak for the Prandtl-Glauert Singularity hypothesis (and who, besides Prandtl and Glauert, presumably, can?), but it's not nitpicky to reinforce the notion that the sound barrier is a barrier in name only, and that it's not a wall of air that manifests in the form of a vapor cone or any other visual phenomenon.
> Maybe it was USN property but signed out semi permanently to Gay...
That would make it even less likely that it was cutting-edge consumer equipment. The Navy may have cutting-edge specialty tech that isn't available in the civilian market, but they generally don't have cutting-edge equipment that is available to civvies; they instead buy from the lowest bidder and budget conservatively for items that're not mission-critical. The Navy had darkrooms on carriers for decades before 2000, so it doesn't stand to reason that they would be early adopters when they already had a plenty-good-enough solution and the infrastructure to report it.
I'd be willing to bet that the Navy didn't budge on digital cameras until a flag officer in the Pentagon Public Affairs Office decided that he needed to leave his mark on the Navy.
posted by Sunburnt at 11:10 AM on February 16, 2016 [1 favorite]
> Maybe it was USN property but signed out semi permanently to Gay...
That would make it even less likely that it was cutting-edge consumer equipment. The Navy may have cutting-edge specialty tech that isn't available in the civilian market, but they generally don't have cutting-edge equipment that is available to civvies; they instead buy from the lowest bidder and budget conservatively for items that're not mission-critical. The Navy had darkrooms on carriers for decades before 2000, so it doesn't stand to reason that they would be early adopters when they already had a plenty-good-enough solution and the infrastructure to report it.
I'd be willing to bet that the Navy didn't budge on digital cameras until a flag officer in the Pentagon Public Affairs Office decided that he needed to leave his mark on the Navy.
posted by Sunburnt at 11:10 AM on February 16, 2016 [1 favorite]
Yeah, sorry, aerodynamics is my day job, I sort of assume that everyone understands that "the sound barrier" is a colloquial term for the speed of sound rather than, like, literally a giant dental dam that materializes out of thin air. So that's a bit of privilege that I retain and yes, you're right, that doesn't happen.
The Prandtl-Glauert model predicts a singularity at Mach 1, so I'm not sure how much they believed their model at that point even back then (I could probably dig up the original paper on NTRS and check). I will say that it's still useful outside of the transonic region (Wikipedia puts that around M 0.7 in that article) and the predictions made are good enough for preliminary design calculations.
posted by indubitable at 11:41 AM on February 16, 2016 [2 favorites]
The Prandtl-Glauert model predicts a singularity at Mach 1, so I'm not sure how much they believed their model at that point even back then (I could probably dig up the original paper on NTRS and check). I will say that it's still useful outside of the transonic region (Wikipedia puts that around M 0.7 in that article) and the predictions made are good enough for preliminary design calculations.
posted by indubitable at 11:41 AM on February 16, 2016 [2 favorites]
if I had to hazard a guess, I'd say that you're seeing a pressure rise
A pressure drop, surely? Increasing the pressure of the local air volume increases the temperature and increases the solubility of water vapor in the air; dropping the pressure suddenly (like, coming off the trailing edge of a wing) would decrease the temperature quickly and cause water vapor to quickly precipitate out and create a cloud.
posted by backseatpilot at 12:15 PM on February 16, 2016
A pressure drop, surely? Increasing the pressure of the local air volume increases the temperature and increases the solubility of water vapor in the air; dropping the pressure suddenly (like, coming off the trailing edge of a wing) would decrease the temperature quickly and cause water vapor to quickly precipitate out and create a cloud.
posted by backseatpilot at 12:15 PM on February 16, 2016
Linked article says it was a Nikon N90. Those were film cameras.
posted by now i'm piste at 12:47 PM on February 16, 2016 [2 favorites]
posted by now i'm piste at 12:47 PM on February 16, 2016 [2 favorites]
I'd genuinely like a brief ELI5 lecture on the sound barrier if it's not too much trouble. I know what I think I know, but it would be really interesting to see how right/wrong that is.
posted by Sebmojo at 12:52 PM on February 16, 2016
posted by Sebmojo at 12:52 PM on February 16, 2016
indubitable: "Yeah, sorry, aerodynamics is my day job, I sort of assume that everyone understands that "the sound barrier" is a colloquial term for the speed of sound rather than, like, literally a giant dental dam that materializes out of thin air. So that's a bit of privilege that I retain and yes, you're right, that doesn't happen.
"
Is it alright that paragraph made me laugh?
I always saw the "sound barrier" as more a symbolic construct than a physical one. You know, all the difficulties we had getting there and all.
posted by Samizdata at 12:52 PM on February 16, 2016
"
Is it alright that paragraph made me laugh?
I always saw the "sound barrier" as more a symbolic construct than a physical one. You know, all the difficulties we had getting there and all.
posted by Samizdata at 12:52 PM on February 16, 2016
... "the sound barrier" is a colloquial term for the speed of sound rather than, like, literally a giant dental dam that materializes out of thin air.
Surely that would be anavel Naval dam, in this case?
posted by Greg_Ace at 12:58 PM on February 16, 2016 [1 favorite]
Surely that would be a
posted by Greg_Ace at 12:58 PM on February 16, 2016 [1 favorite]
A pressure drop, surely?
Yeah, I misspoke there.
posted by indubitable at 1:03 PM on February 16, 2016
Yeah, I misspoke there.
posted by indubitable at 1:03 PM on February 16, 2016
literally a giant dental dam that materializes out of thin air
DOCTOR TEETH AND THE TRANSONIC MEMBRANE
posted by a halcyon day at 2:04 PM on February 16, 2016 [1 favorite]
DOCTOR TEETH AND THE TRANSONIC MEMBRANE
posted by a halcyon day at 2:04 PM on February 16, 2016 [1 favorite]
ELI5
There was a demon that lived in the air...
Sorry :)
posted by anonymisc at 5:02 PM on February 16, 2016 [1 favorite]
There was a demon that lived in the air...
Sorry :)
posted by anonymisc at 5:02 PM on February 16, 2016 [1 favorite]
That is one weird chemtrail.
posted by Conrad-Casserole at 7:37 PM on February 16, 2016
posted by Conrad-Casserole at 7:37 PM on February 16, 2016
Sadly, digital photography can't produce the beautiful real film grain shown in this picture.
posted by Dean358 at 5:32 AM on February 17, 2016
posted by Dean358 at 5:32 AM on February 17, 2016
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posted by the man of twists and turns at 8:56 AM on February 16, 2016 [6 favorites]