(1) Talon Torres's answer to What is the fastest speed of any object on the earth? - Quora

(1) Talon Torres's answer to What is the fastest speed of any object on the earth? - Quora:



Two words. Manhole cover.

Two words. Manhole cover.

You
may think I'm crazy. "How can a manhole cover be faster than New
Horizons", you ask. "What are you on," you ask. Just hear me out.

From SavvyParanoia on Wordpress:

"The
Holy Grail of space-minded dreamers and researchers has always been
nuclear-powered propulsion. Nuclear-powered propulsion would be far
cleaner, far cheaper, far more efficient, and far less noisy than
current roar-and-a-fireball rocket propulsion. (Not sure the last is an
advantage. I’m a big fan of roar-and-a-fireball in almost anything,
including rocket launches, howitzers, and NASCAR races.)

And
in fact we’ve had nuclear propulsion for some time. The small
maneuvering engines of deep-space probes are typically nuclear-powered,
but not in the way usually envisioned: They are tiny, nearly soundless
(even on Earth) little fast-particle emitters that generate fractions of
an ounce of thrust. That’s enough to rotate a spacecraft, given time,
and their nuclear sources last virtually forever, but they’re hardly the
earth-shaking monsters we envisioned blasting from Earth into space.
Too bad we’ve not been able to accomplish that.

Or have we? In a round-about way I recently came across the Nuclear Weapons Archive,
a wonder world of historical documents, photos, and personal accounts
of the Nuclear Age as seen through the history of nuclear bombs and bomb
tests. For the historian, the scientist, or the intellectually curious
the whole archive is a trove of riches, every link and page another
revelation. Jump in anywhere and start reading — you’ll be hooked. And
it’s not just about the U.S. nuclear program — it has material covering
every declared and non-declared nuclear power.

For illustration I’ll pass along just one event documented in the archives that by itself merits a whole book and a movie:

While
all the early nuclear tests had been above ground (what could possibly
be wrong with that, right?), by 1956 Los Alamos was working on how to
contain radiation and fallout by detonating the bombs underground.
Initially the concept was very simple: drill a deep hole, say, 500 feet
deep by four feet wide, lower the bomb to the bottom, light the fuse and
run. (Well, OK, not quite that simple. But the hole was.) Originally
the idea was to leave the holes uncapped, the thinking being that even
with the top of the shaft open relatively little would escape. (Which
was largely true, though not exactly up to modern expectations.)

By
mid-1957 Los Alamos scientist (and famed astrophysicist) Robert
Brownlee was ready to try testing with a capped shaft (known as a
“stemmed” shaft in nuke-speak). In a test known as Pascal-A, a cap of
four-inch-thick solid steel — what one might call the biggest, baddest
manhole cover in history — was securely welded to the top of the shaft.
With nothing else in the way, that far from the bomb the plate would
likely have popped off, but wouldn’t have gone very far.

But something else was
in the way. Way down the shaft, hundreds of feet below the cap, was a
collimator, a five-foot-thick, multi-ton plug of concrete with a small
hole in the middle. The hole served as a small window through which a
special detector attached to the inside of the steel cap could make
measurements during the first few milliseconds of the explosion. After
that first fraction of a second the detector itself would be
annihilated, but its brief set of readings would have been captured by
above-ground recorders.

It’s significant
that what was being tested in Pascal-A was an experimental bomb that was
designed to be “one point safe.” That meant that if it was accidentally
detonated (a significant concern back then), it would only fire only
one of its many trigger points around the explosive core, resulting in a
tiny fraction of the yield, not the whole megillah. The explosion in
the test was therefore expected to be (relatively) very small.

That’s not quite what happened.

At
10:35pm on August 27, 1957 in Area U3d of the New Mexico Nuclear Test
Site, the bomb was detonated. But instead of the expected small yield
the bomb detonated with a yield approximately five orders of magnitude
greater than expected (that’s about 100 000 times greater). The blast
instantly vaporized the entire multi-ton concrete collimator and shot it
up the tube as a multi-ton wave of vaporized matter at extremely high
temperature, pressure, and velocity. The shaft had, in effect, become a
enormous 500-foot long, four-foot wide gun barrel with the energy of
billions of pounds of TNT released at one end and, at the other end, the
now insignificantly small metal cap, about the equivalent of a bottle
cap on the end of a naval gun.

As it
happens, a very high speed film camera was recording the event and was
expected to capture in slow motion the path and speed of any ejecta from
the hole. Unfortunately, the camera, which had quite a wide view of top
of the hole and and the area around and above, recorded the “manhole
cover” on only one frame. There was no malfunction of the camera, it’s
just that the “manhole cover” blasted out of sight so fast that the
camera only saw it for one frame. Later calculations showed that the
heretofore mundane four-foot metal disk had been launched at six times Earth’s escape velocity. That’s one hundred fifty thousand miles per hour. Forty-five miles per second.
Nine times faster than the Space Shuttle, six times faster than the
fastest moon rockets. Faster than the Voyager spacecraft, which, having
reached over 35000 miles per hour, are now leaving the solar system and
have for years been claimed to be the fastest man-made objects ever. To
which I now say: Pshaw and poppycock — the Pascal-A “manhole cover” in a
fraction of a second achieved more than four times the speed it took
Voyager 1 decades to attain.

The “manhole
cover” was, of course, never found. And, to my deep disappointment,
cold-sober calculations indicate it’s not on its way to the Hercules
Cluster which, late on a summer night shot from a vertical hole in New
Mexico, may well be about where it was aimed. Instead it almost
certainly suffered a meteor’s fate in reverse: At such an extreme speed
it would have created an enormous fireball (a fireball going up) and been slowed so much that what didn’t burn off would eventually have come back down.

Being
such a tough and massive object, most of it would have survived its
“reverse re-entry” (or just plain “entry”?), so it would have come down
as a burned, edge-melted, and perhaps quite misshapen chunk of solid
steel, a very formidable projectile that would have done very serious
damage even to large buildings. Given that no one that night reported
any macerated cars or demolished buildings and that the huge object had
been launched nearly vertically, it likely came down in the desert
somewhere in the wide vicinity of the test site in New Mexico. It would
have had some serious hang-time, though.

So
somewhere in the New Mexico desert, unknown and unmourned, lies an
American relic, a piece of history like no other: the fastest man-made
object ever. And I harbor the hope that, whether it’s found or not, our
nation and the world of science will someday realize our error all these
years and recognize that the Pascal-A Manhole Cover, not Voyager 1, is
the fastest man-made object ever."