Neil deGrasse Tyson Admits He Was Wrong On Deflategate
It doesn't happen very often, but astrophysicist Neil deGrasse Tyson was wrong this week. And like any good scientist, he's not afraid to admit it, correct it and explain himself.
On Monday, the director of the Hayden Planetarium at the American Museum of Natural History took to Twitter in an attempt to deflate the New England Patriots' Deflategate excuse.
Coach Bill Belichick had said atmospheric pressures and balls being transported from the warm indoors out onto a cold field could have caused them to lose enough pressure to fall below league standards. But Tyson tweeted that to lose as much pressure as the balls did, they would need to be inflated with 125-degree air.
"My calculation used the well-known gas formula that relates pressure to temperature within a fixed volume," Tyson explained on Facebook on Tuesday. "Quite simply, the two quantities are directly and linearly related. e.g. Halve the temperature, you've halved the pressure. Triple the temperature, you've tripled the pressure."
He wrote that his mistake was using absolute pressures instead of gauge pressures. Going by gauge pressures, the balls would need to be inflated with 90-degree air.
"A delightfully moot point since neither temperature absolves the NE Patriots even as we all know that the NE Patriots, in their 45 to 7 victory over the Colts, would have won the game no matter the ball pressure," he wrote. "And, as far as I am concerned, the Patriots would have won that game even in the vacuum of space."
Tyson could have left it at that. But he didn't, adding a postscript that explains how these same calculations are at work in far more significant ways than football deflation:
Here's his full explanation, as posted on Facebook:
DeflateGate
January 27, 2015 at 5:07pm
Monday, January 27, 2015
Having resisted for a week, yesterday I posted a tweet weighing in on DeflateGate - the accusation that the New England Patriots, in their trouncing of the Indianapolis Colts, slightly deflated their contributed game balls.
Here is the tweet:
"For the Patriots to blame a change in temperature for 15% lower-pressures, requires balls to be inflated with 125-degree air."
My calculation used the well-known gas formula that relates pressure to temperature within a fixed volume. Quite simply, the two quantities are directly and linearly related. e.g. Halve the temperature, you've halved the pressure. Triple the temperature, you've tripled the pressure.
Shortly afterwards, many of my physics-fluent twitter followers, as well as others in the blogosphere, were quick to point out that in my calculation I neglected to account for the fact that the football pressures were "gauge" pressures (as would be the pressures measured in any ball on Earth) rather than "absolute" pressures. And the calculation that I performed applies only to absolute pressures -- which reference the case where the football pressure is measured in the vacuum of space, without the effects of atmospheric pressure on the measurement. Using the (correct) gauge pressure in the calculation reduces the needed inflation temperature to about 90-degrees for that effect.
This is simply an oversight on my part, and I'm glad so many stepped forward to correct it. But what it means is that the Patriots would simply need to have inflated the balls with (more accessible) 90 degree air rather than 125 degree air. A delightfully moot point since neither temperature absolves the NE Patriots even as we all know that the NE Patriots, in their 45 to 7 victory over the Colts, would have won the game no matter the ball pressure. And, as far as I am concerned, the Patriots would have won that game even in the vacuum of space.
As Always, Keep Looking up.
-Neil deGrasse Tyson, Chicago
p.s. Using the same formulas, if you keep pressure the same, the temperature and volume scale in the exact inverse of one another. Double the volume of a gas the temperature will drop by half. A version of this principle even applies to the universe itself. When the famous cosmic microwave background was formed, the temperature of the universe was about 3,000 degrees (K). Since then, the universe has expanded by a factor of 1000, dropping the temperature to 1/1000th of 3,000 degrees. Or about 3 degrees (K), the current temperature of the universe.
p.p.s. If you want to see more of how physicists makes approximations, have a look at this essay from several years back:
http://www.haydenplanetarium.org/tyson/read/1997/03/01/on-being-round which was excepted for the book "Death By Black Hole", if you are interested: http://www.haydenplanetarium.org/tyson/buy/books/death-by-black-hole
http://www.huffingtonpost.com/2015/...gate_n_6560340.html?ncid=txtlnkusaolp00000592
It doesn't happen very often, but astrophysicist Neil deGrasse Tyson was wrong this week. And like any good scientist, he's not afraid to admit it, correct it and explain himself.
On Monday, the director of the Hayden Planetarium at the American Museum of Natural History took to Twitter in an attempt to deflate the New England Patriots' Deflategate excuse.
Coach Bill Belichick had said atmospheric pressures and balls being transported from the warm indoors out onto a cold field could have caused them to lose enough pressure to fall below league standards. But Tyson tweeted that to lose as much pressure as the balls did, they would need to be inflated with 125-degree air.
"My calculation used the well-known gas formula that relates pressure to temperature within a fixed volume," Tyson explained on Facebook on Tuesday. "Quite simply, the two quantities are directly and linearly related. e.g. Halve the temperature, you've halved the pressure. Triple the temperature, you've tripled the pressure."
He wrote that his mistake was using absolute pressures instead of gauge pressures. Going by gauge pressures, the balls would need to be inflated with 90-degree air.
"A delightfully moot point since neither temperature absolves the NE Patriots even as we all know that the NE Patriots, in their 45 to 7 victory over the Colts, would have won the game no matter the ball pressure," he wrote. "And, as far as I am concerned, the Patriots would have won that game even in the vacuum of space."
Tyson could have left it at that. But he didn't, adding a postscript that explains how these same calculations are at work in far more significant ways than football deflation:
"A version of this principle even applies to the universe itself. When the famous cosmic microwave background was formed, the temperature of the universe was about 3,000 degrees (K). Since then, the universe has expanded by a factor of 1000, dropping the temperature to 1/1000th of 3,000 degrees. Or about 3 degrees (K), the current temperature of the universe."
Here's his full explanation, as posted on Facebook:
DeflateGate
January 27, 2015 at 5:07pm
Monday, January 27, 2015
Having resisted for a week, yesterday I posted a tweet weighing in on DeflateGate - the accusation that the New England Patriots, in their trouncing of the Indianapolis Colts, slightly deflated their contributed game balls.
Here is the tweet:
"For the Patriots to blame a change in temperature for 15% lower-pressures, requires balls to be inflated with 125-degree air."
My calculation used the well-known gas formula that relates pressure to temperature within a fixed volume. Quite simply, the two quantities are directly and linearly related. e.g. Halve the temperature, you've halved the pressure. Triple the temperature, you've tripled the pressure.
Shortly afterwards, many of my physics-fluent twitter followers, as well as others in the blogosphere, were quick to point out that in my calculation I neglected to account for the fact that the football pressures were "gauge" pressures (as would be the pressures measured in any ball on Earth) rather than "absolute" pressures. And the calculation that I performed applies only to absolute pressures -- which reference the case where the football pressure is measured in the vacuum of space, without the effects of atmospheric pressure on the measurement. Using the (correct) gauge pressure in the calculation reduces the needed inflation temperature to about 90-degrees for that effect.
This is simply an oversight on my part, and I'm glad so many stepped forward to correct it. But what it means is that the Patriots would simply need to have inflated the balls with (more accessible) 90 degree air rather than 125 degree air. A delightfully moot point since neither temperature absolves the NE Patriots even as we all know that the NE Patriots, in their 45 to 7 victory over the Colts, would have won the game no matter the ball pressure. And, as far as I am concerned, the Patriots would have won that game even in the vacuum of space.
As Always, Keep Looking up.
-Neil deGrasse Tyson, Chicago
p.s. Using the same formulas, if you keep pressure the same, the temperature and volume scale in the exact inverse of one another. Double the volume of a gas the temperature will drop by half. A version of this principle even applies to the universe itself. When the famous cosmic microwave background was formed, the temperature of the universe was about 3,000 degrees (K). Since then, the universe has expanded by a factor of 1000, dropping the temperature to 1/1000th of 3,000 degrees. Or about 3 degrees (K), the current temperature of the universe.
p.p.s. If you want to see more of how physicists makes approximations, have a look at this essay from several years back:
http://www.haydenplanetarium.org/tyson/read/1997/03/01/on-being-round which was excepted for the book "Death By Black Hole", if you are interested: http://www.haydenplanetarium.org/tyson/buy/books/death-by-black-hole
http://www.huffingtonpost.com/2015/...gate_n_6560340.html?ncid=txtlnkusaolp00000592
