Item — HN Reader

>"Time Of Flight Sensors

Recently the cost of these Time Of flight Sensors (TOF) have plummeted and have made a new type of Theremin possible. The TOF sensors are small lasers combined with a very fast photodiode, these clever little devices are able to measure the time that the light from the laser takes to your hand, be reflected, and received by the photodiode. Even more impressive they can do this with millimetre precision."

Never knew these existed until reading this(!)... let's learn more about them:

Apparently, a "Time Of Flight Sensor" is also called a "Time Of Flight Camera":

https://en.wikipedia.org/wiki/Time-of-flight_camera

Now, me I'm wondering if this could be used to make a Gravity Wave detector of some sort... oh sure, it wouldn't have as much precision as an Interferometer specifically created for that purpose... but maybe you could detect something, under some as-of-yet unknown conditions... like maybe if you had a big enough electromagnet or wave emitter or something (or thing that creates or captures or focuses Gravity Waves, no matter how small or faint -- you decide what it is!), maybe you could influence the distance perceived by the device some really small amount (1 millimetre?), which might indicate the presence of an altering/interfering field (Gravity, something else?) of some sort...

And then again, maybe not!

Still, a very interesting device to potentially experiment with, in different contexts...

Great article, too!

2 comments

Unfortunately, this is not possible. Gravity-wave detectors are incredibly, incredibly more sensitive than what you might have expected.

The only devices that are currently able to detect gravity waves are huge interferometers [0]. Light gets reflected many times in the arms of these interferometers and after having travelled a distance of approximately 1000km (over 600 miles), the change in length effected by gravity waves is in the order of a fraction of the diameter of a proton (a millionth of a billionth of a meter shouldn't be off by to much).

[0] https://en.wikipedia.org/wiki/LIGO

You could be right!

When I think about it, Today's science first has to be able to show methods for slowing down, stopping, reversing (and speeding up, if slowing down can be accomplishd) plain old electromagnetic waves with plain old electromagnetic devices.

Once we can do all of that, then and only then will we be ready for Gravity Waves, and that's if they exist exactly as speculated upon...

Yes, I know there are some experiments with equipment costing billions of dollars that measure things on a scale which is unobtainable to most average science practitioners, and as a result of those incredibly small measurements, Gravity Waves are said to exist...

The problem I have is that if I can't perform an experiment with equipment costing less than say, $1000, then how am I supposed to verify, much less reason correctly, about Gravity Waves?

It's like today's News Media -- where they claim something happened thousands of miles away -- but I wasn't there, I didn't see it, I don't have firsthand witnessing of the event -- how do I know it happened, and if I allow that it happened, then how do I know that it happened exactly as the other people who allegedly did, claim?

A Tesla Coil, on the other hand, can be built for under $10, and allows me to indpendently verify, firsthand, by direct experimentation -- all of Tesla's theories!

So, how do I do the same thing with Gravity Waves, if they indeed exist as described by people with billions of dollars of equipment, and the ability to take measurements several orders of magnitude tinier than I am able to?

How do I know that the Gravity Wave scientists -- are telling the truth?

But more importantly, how do I know that the Gravity Wave scientists -- are reasoning correctly?

> some really small amount (1 millimetre?)

Heh, your "really small" is too large by at least nine orders of magnitude. That’s got to be some sort of a record.

If this is a comfort, GP, then check out this prediction.

https://en.wikipedia.org/wiki/Cosmological_constant_problem

Single digit orders of magnitude off are suddenly not even so bad ;)

Even more baffling than quantum field theory not being consistent with observation in this particular case is that it apparently admits calculations for the same quantity that differ by 70 orders of magnitude.