danielmittleman

5 ms·

1.
by danielmittleman 5y ago
We have been (reluctantly) using the term "6G" in grant proposals for several years now. It's not that new, actually.
2.
by danielmittleman 5y ago
Actually, here's a fun fact: the audio "chirp" that you have heard in association with black hole mergers is not slowed down. The measurement is a gravitational wave, of course, not a sound wave. But when it is played as a
3.
by danielmittleman 5y ago
True, but the article is all about electromagnetism, not acoustics. I'm sure the author of the article was not the same person as the person who made the graphics. They probably ought to have communicated with each other a bit more cl
4.
by danielmittleman 5y ago
The atmospheric transmission's dependence on frequency is complicated. There are water vapor resonances above 100 GHz which one would want to avoid. There is frequency-dependent scattering from droplets, and there is a continuum backgr
5.
by danielmittleman 5y ago
Well, actually it's much easier at lower frequencies. After all, your cell phone operates at around 2.5 GHz (if it is a 4G phone). But yes, there are huge challenges involved in using higher frequencies for communications. We will ev
6.
by danielmittleman 5y ago
Your eyes cannot see THz radiation, so no. It's invisible to the human eye. Like microwaves. But yes, it is possible to produce a beam. Also: to be fair, the challenge in finding efficient sources is really only one of the challenges
7.
by danielmittleman 5y ago
That question of the sound quality is actually a question of the bandwidth used to encode the transmission. It is naturally easier to access a broader bandwidth if the frequency is higher. But there is a point of diminishing returns. You d
8.
by danielmittleman 5y ago
Yea, that's confusing, despite not being wrong. It is a juxtaposition of two completely distinct phenomena on one graphic, which is confusing, for sure. But the whole article is about EM waves, not sound waves. Sigh.
9.
by danielmittleman 5y ago
I like your enthusiasm.
10.
by danielmittleman 5y ago
By now, it has become standard terminology in the research community to use the phrase "terahertz radiation" to mean EM waves between 0.1-10 THz (although some people prefer 0.3-30 THz, and there are also other options out there).
11.
by danielmittleman 5y ago
To be clear: there is NOTHING at all about sound in this article. The spectrum does not show a continuum from sound to light. It shows the electromagnetic spectrum, which does not contain any sound waves at all. One can encode acoustic i
12.
by danielmittleman 5y ago
No that's not it. There is NOTHING about sound in that article. It is ALL about electromagnetic waves, which are NOT sound waves. Sound waves are pressure variations in the air. Electromagnetic waves do not require air. They are oscil
13.
by danielmittleman 5y ago
Yes. We do it all the time. In some sense, the tricky part is not the antenna itself. It's the electronics that you use to drive it. Electronics can be fast enough to drive an antenna at a few GHz, which is why it is easy to generat
14.
by danielmittleman 5y ago
It does not say that we can't produce terahertz. It says that there are no consumer products that make use of terahertz, because (among other reasons) producing it is more challenging than, say, producing microwaves. That statement i
15.
by danielmittleman 5y ago
Light IS an electromagnetic wave, so to say it has similar properties to EM waves is kind of like saying that pizza has similar properties to food. Also not sure what you mean by "needs a vacuum to make it possible" seeing as we g
16.
by danielmittleman 5y ago
There's a lot of misinformation in the comments posted here. Maybe this bit of information will help. The phrase "terahertz radiation" refers specifically to the band of the electromagnetic spectrum lying between 0.1 THz and