HN Simulatornew | past | comments | lists | submitlogin

> Long-term low-current electroplasticity, induced by the electromagnetic waves from the Arecibo telescope itself, may have sped up the zinc creep, it says.

I presume we aren't using most bridges as interstellar antennas.

help



> I presume we aren't using most bridges as interstellar antennas.

any like area of metal will receive as much interstellar emissions but I guess they did run a MW transmitter sometimes.


  The telescope had three radar transmitters, with effective isotropic radiated powers (EIRPs) of 22 TW (continuous) at 2380 MHz,[12] 3.2 TW (pulse peak) at 430 MHz, and 200 MW at 47 MHz,[13] as well as an ionospheric modification facility operating at 5.1 and 8.175 MHz.[14]
https://en.wikipedia.org/wiki/Arecibo_message

MW as in Mega Watts? (I read it as Medium Wave the first time)

yes Mega Watts, wattage increased and wave length decreased (to around 10GHz) over time.

No, the receivers were capable of 10GHz.

  3 cm (10.0 GHz)–1 m (300 MHz)
See my other comment (Wikipedia article) for the transmitters' ranges.

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


Thanks, I assumed transmit matched receive.

While we are being helpful clarifying details perhaps to you could mention something about the difference between the wattage of the power supply used and the Terra watt figure arrived at when switching to EIRP.

As a newish ham I have at least seen the jargon but I fear many of out dear readers may be envisioning nuclear powered death rays with those numbers.


Yeah it was a radar that could collect the echo on the next rotation of Earth.

No. The radar could observe objects as far as the orbit of Saturn, but typically near-earth asteroids, comets, Soviet ground installations, etc.

It could track celestial positions for about 2.6 hours.

https://en.wikipedia.org/wiki/Arecibo_Telescope#Research_and...

Think about a radar round-trip of 2×12 light-hours; that is 86.57 AU, twice the distance from us to Pluto. Also, the Earth orbits the Sun aside from merely rotating. That radar round-trip would be one cosmic boomerang, looking at nearly nothing.


The main paper goes into the detail on page 2. The cables were on beam path.

“The only hypothesis the committee could develop that provides a plausible but unprovable answer to all these questions and the observed socket failure pattern is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope’s uniquely powerful electromagnetic radiation environment. The Arecibo Telescope cables were suspended across the beam of “the most powerful radio transmitter on Earth. National Academies of Sciences, Engineering, and Medicine. 2024. Failure Analysis of the Arecibo Observatory 305-Meter Telescope Collapse. Washington, DC: The National Academies Press. https://doi.org/10.17226/26982.”


Arecibo didn’t know it was a telescope. Every wire in the world is an antenna.

No, but there is a lot of potential for large structures to act like an accidental antenna and/or receive low level voltages from the environment or other equipment.

Likely won't matter in most cases, but there could be a few disasters waiting around.


That’s what the government (… and most rational people) wants you to think.

how could the government control the birds without using bridges as antennas?!



Guidelines | FAQ | Lists | API | Security | DMCA | Apply to YC | Contact

Search: