a new #AstroPhysicsFactlet with quite some range:
Astronomers (not like me, real hardcore astronomers!) collect photons to observe the Universe and study its properties in space and time.
How large is the range of wavelengths of the photons they use for this?
The basic formula to relate the wavelength (λ) of a photon with its associated energy (E) is the famous:
E=hc/λ, where h=Planck constant and c=speed of light.
The lowest frequency observational astronomy picks up radio waves, i.e. electromagnetic fluctuations with wavelengths up to λ~30m (~10MHz)
At the opposite range of the spectrum we now have ~100 Tera-electron volt observations in the extreme γ-ray domain:
The range of scales probed by astronomy, using different photons and techniques, is so incredibly large:
from λ(radio)~10m to λ(gamma)~1e-20m, i.e. ~21 decades of range!
😱
(fun fact: I admit I have never fully realised this was so large before making this thread)
This explains the radically different techniques used by observational astronomers to extract informations from telescopes in these very different energy ranges.
At the end of the story all are maps and spectra and such, but the pipelines and art of reducing raw data from these opposite side of the EM spectrum are astonishgly different.
Now, how does a ~21 orders of magnitude range in the "size" of photons, which are the "beasts" which astronomers typically are hunting for?
(images: Dall-E answer to "comic-like impression of an astronomer hunting for photons, drawn like in the Simpsons cartoon" 😄 )
The 21 orders of magnitude range is much, much larger than what we can consider as the range of living organisms typically targeted (**my wild guess!**) by biologists, which goes from ~nanometers (1e-9m) to ~10m (whales/dinosaurus/trees...), giving a ~10 orders of magnitude spread across the size of "beasts".
@franco_vazza
Some species have root networks that can be on the order of a kilometre think, the sort of thing that happens when a species can just grow new bits indefinitely
@tobychev
Cool! then, the "biological range of beasts" will be more about ~1e12, still tiny compared to the ~1e21 range of photons!