Katherine Mangu-Ward | July 23, 2009
From the New York Times correction page, July 17, 1969:

Via the marvelous Regret the Error blog.
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The NYT has enough recent corrections that are hilarious.
There's really no need to research old ones.
That one, would be a good exception is.
What is amazing about that article is that it was written in 1925. The idea that there was an ether and you had to push against something to move died in the late 19th Century. Anyone who took a college level physics course in 1925 would have known that editorial was bunk.
Sorry. The retard got loose for a while. It's not easy hiding this much stupid.
JB, retard is no longer socially acceptable. Please use the word liberal in it's place.
Let me know when they apologize for Stalin.
Jeez Warren, it only took them 49 years to apologize to Goddard.
You can't rush these things you know.
So, the NYT has been populated with idiots since the 1920s at
least? Good to know. BTW, anyone know where the NYT was on the
"OMFG! We're all going to die in a new ice age!" fad back in the
1970s?
-jcr
That "Ice Age" thing was always a minority opinion anyway.
I have a collection of Isaac Asimov essays from the early 1960s in
which he talks about global warming.
The NYT in 1920 said of Robert Goddard:"he only seems to lack
the knowledge ladled out daily in high schools." I guess that is
what made him so smart.
Interesting how little has changed in 89 years.
The idea that there was an ether and you had to push against
something to move died in the late 19th Century. Anyone who took a
college level physics course in 1925 would have known that
editorial was bunk.
The ether wasn't supposed to affect anything but light. It was also
presumed to be present everywhere in space, so that a vacuum wasn't
really a vacuum. That's not the issue here.
A rocket is pushing against something, even in a vacuum. Roughly
speaking, it's pushing against the gases that are expelled from the
engine. Of course, this was known in the 1700s so your main point
is correct.
A rocket is pushing against something, even in a vacuum.
Roughly speaking, it's pushing against the gases that are expelled
from the engine.
I thought it was the other way around - that is, the expanding
gases are doing the pushing.
Really, pushing is the wrong way to think of it. The exhaust
thrown out of the engine is not pushing against anything. There is
simply a high pressure chamber full of molecules bouncing back and
forth against the chamber walls very fast. Open a hole on one end,
and the molecules fly out -- never to be seen again. It is simple
conservation of momentum that the rocket will go the other
way.
There are ways to capture more energy from the molecules leaving
the hole in the chamber by placing a parabolic bell on the engine.
Those ejected gasses that hit the bell and are consequently
deflected directly rearward from the rocket really are pushing on
the rocket.
The idea that there was an ether and you had to push against
something to move died in the late 19th Century. Anyone who took a
college level physics course in 1925 would have known that
editorial was bunk.
I don't think the 1920 editorial actually existed. It was a little
joke by the 1969 Corrections Page editor, wasn't it?
Really, pushing is the wrong way to think of it. The exhaust
thrown out of the engine is not pushing against
anything.
I didn't mean to say that the exhaust was pushing against anything
outside of the engine. I was taught to think of a rocket's
combustion chamber like a bomb or controlled explosion, and the
rocket's motion as an example of an action producing an opposite
and equal re-action. In other words, whether gases, steam, or even
ions are ejected out the nozzle, it's the same principle as if one
stood in a boat on the water (or an imaginary raft in space) and
threw rocks away from it - the boat (or raft) will move.
If it's a massive enough rock and/or it's thrown hard enough (to overcome inertia?)
I don't think the 1920 editorial actually existed. It was a
little joke by the 1969 Corrections Page editor, wasn't
it?
As one of the commenters on the RtE post noted,
it does indeed exist (although you'll need to scroll down a
little within the PDF).
We would like to apologize for a multitude of errors we made in the 1930's where we describe 'rosy cheeked milk maidens' in the Ukraine 'singing wholesome songs praising Stalin and the glorious Communist Revolution'. We meant 'gaunt faced and starving women on the brink of dying' and, 'singing songs of propaganda praising Stalin and the Communist Revolution so as not to be shot.'
Really, pushing is the wrong way to think of it. The exhaust
thrown out of the engine is not pushing against anything. There is
simply a high pressure chamber full of molecules bouncing back and
forth against the chamber walls very fast. Open a hole on one end,
and the molecules fly out -- never to be seen again. It is simple
conservation of momentum that the rocket will go the other
way.
Yes, but those molecules *push* on the walls of the chamber when
they bounce off of it. Conservation of momentum isn't some axiom of
physics, it's a direct consequence of Newton's 3rd (ie,
action-reaction).
I guess it would be more precise to say the rocket is propelled by
the removal of the force of the molecular collisions against the
back wall of the chamber. (Of course discussing conservation laws
is kind of inappropriate anyway since the chemical reaction within
the fuel is adding mechanical energy to the system)
That's exactly it: What propels the rocket is that the high
pressure gasses are not pushing on the exhaust port in the
back.
Blow up a balloon. Don't tie it. Let it go.
It is not really accurate to say that the balloon flies because the
air is pushing on the front of the balloon from the inside. The air
was doing that no less before you let the balloon go. What's
different when you let the balloon go is that air is no longer
pushing on the back of the balloon from the inside.
As one of the commenters on the RtE post noted, it does
indeed exist (although you'll need to scroll down a little within
the PDF).
That link was to a PDF of what appeared to be an old newspaper
clipping. In fact, though, that clipping was fabricated by NASA the
same week they were simulating the moon landing on a sound
stage.
Har har, I like where the editorial goes on to criticize Jules Verne's depiction of using rocketry to escape moon orbit.
(Seriously, though, the *correction* was run the same week as
the Apollo 11 flight. The folks at the NYT seemed to think the
timing was right. (And I actually went to the microfilm in my high
school library to read the original 1920 editorial.) Later that
summer, went on a family vacation from DC to the North Shore of
Massachusetts. On the way, we stopped in Auburn, Massachusetts, to
find the site where Goddard fired off the world's first
liquid-fueled rocket. It was in the middle of a golf course that
used to be his aunt's farm, marked by an obelisk. There's a picture
somewhere of my brother and me standing next to it.
(Other highlights of that vacation: reading how the New York Times
initially denounced those hippies gathered at Woodstock, then made
a 180-degree course correction and saying never mind, it's really
kinda groovy, proving that it doesn't always take them 49 years to
change their mind.)
JB, retard is no longer socially acceptable. Please use the
word liberal in it's place.
Same difference.
@Tulpa: Actually, I would consider conservation of momentum a
more axiomatic principle of physics than Newton's third law (or any
of his laws). Conservation laws -- specifically those of mass and
energy -- are the most universally applicable physical laws.
Of course, all of these "laws" are results, not causes. Simply a
way to identify aspects of the continuum of physical reality in
ways that humans can understand and analyze. As Robert Pirsig would
say, they are nothing more than ghosts inhabiting the Church of
Reason.
they are nothing more than ghosts inhabiting the Church of Reason.
Drink!
But seriously, well said.
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