Name: 那次我們給了地球一個由幾百萬根小針組成的戒指 (That Time We Gave Earth a Ring Made of Millions of Tiny Needles)
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第二類條件句型

Have you ever wondered what Earth would be like if it had a big, gorgeous ring like Saturn's?

程度副詞

Well, in the 1960s, we did almost put a ring on Earth.

Starting in 1961, the US military tried to launch hundreds of millions of tiny copper

needles into space to create a reliable boost for their communications systems.

At the time, if the US wanted to send long-range messages to their allies on the other side

of the Atlantic, they had two main options:

They could send them through undersea cables, or by bouncing radio signals off of the ionosphere,

a layer of the upper atmosphere that stretches from about 50-1000 kilometers up.

The ionosphere is full of charged particles like ions and electrons, which means you can

sometimes use it as a kind of long-range, signal-boosting antenna.

When radio waves hit electrons in the ionosphere, they vibrate at the same frequency as the radio wave.

And as they vibrate, they emit radio waves of their own, bouncing the signal back down to Earth.

The problem was that neither of these approaches are fool-proof.

Undersea cables can be sabotaged, and since this was the Cold War, sabotage was business as usual.

And the ionosphere is really unpredictable.

The number of electrons available to carry a signal changes with the seasons, solar weather,

and plenty of other factors that we still don't understand.

So, the US military wanted a system that was reliable and beyond sabotage.

They decided that if the ionosphere wasn't reliable for sending messages, well, they'd

The idea was to launch 480 million copper needles into space where they would fill the

orbit they were placed into, creating a ring.

The needles were each 1.28 centimeters long, and about as thin as a human hair.

During the testing phase, each of these copper needles would help boost the signal for a

receiver dish in the town of Westford, Massachusetts.

But eventually, other sites would be able to use the communications ring, too.

The needles would work by acting as little dipole antennas.

At its simplest, a dipole antenna is basically a wire that's exactly the right length to

When you carefully match the signal to the antenna this way, it creates a standing wave,

where the vibrations of the electrons in the needle bolster one another to produce a strong radio wave.

That stronger radio wave can then be picked up by other needles, or by stations on the ground.

The first batch of needles was launched on October 21, 1961.

The needles were in a cylinder, embedded in naphthalene, otherwise known as mothballs.

But they didn't choose that compound because they wanted the needles to smell like your

grandmother's closet; naphthalene was convenient because it would evaporate in the near-vacuum of space.

The idea was that when the cylinder was released, it would spin, creating a force on the needles

That force, combined with the evaporation of the naphthalene, would disperse the needles.

The test failed because even though the needles were pushed out of the cylinder, there were

so many crammed into such a tight space that they clumped together into about a half dozen big clusters.

But in May of 1963, the military tried again, putting 350 million more needles into 5 smaller

The needles transmitted radio signals much more reliably than our natural ionosphere,

and it would've been pretty tough for the Soviet Union to go up there and destroy the ring.

So if the test was successful, and the idea worked, why aren't we constantly bragging

Well, the main reason is that satellites became a thing pretty soon after that.

And they were a way better solution than Project West Ford.

Satellites are easier to put into orbit, can transmit and relay a much wider range of microwave

and radio wave signals, and can be actively controlled and pointed at different things.

Plus, it's a lot easier to fit a camera on a satellite than on a tiny copper needle.

The other reason we don't use a giant ring of needles anymore is that there was a lot

Interference from the needles would've messed with sensitive telescopes, and there were

a lot of people accusing the U.S. of “dirtying space”.

So the military shelved Project West Ford, and Earth doesn't have a ring of tiny needles.

But some leftovers from the project are still out there.

The needles they launched were meant to fall to Earth within a few years, but dozens of

batches of them are still being tracked by NASA, including plenty of clumps from that

Which is a lot of debris from just a couple of early tests.

If nothing else, Project West Ford helped to shape how we treat the space around our

planet, and made us much more aware of the debris we put up there.

Today, the project stands as a both ridiculous and wonderful testament to our capacity to

And as the time humanity tried to turn Earth into a mini-Saturn.

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