Astronomers say that they didn`t notice indications of extraterrestrial civilization anywhere around.
I wonder can we actually see aliens with our telescopes. Why do I ask this question? Because light from distant objects travels very long to reach us. Let us take in the consideration exoplanet Kepler 452b which is aprox. 1400 ly from Earth. We can use anything distant for this purpose. At the present moment we see it as it was 1400 years ago. Therefore we must wait 1400 years to see how it looks now. Or we can use something which is called optical magnification.
I have found data for Earth`s best magnification telescope: Keck 17500x.
Others fall much behind: Subaru 7500x, Yale 4850x, Hubble 2880x, etc.
I can not find Webb optical magnification power nor focal lenght of its eyepiece. The only fact I found is comparison with Hubble stating that Webb can see 10 to 100 times better. I guess it means that it has 28.800 to 288.000 optical power. Please correct me here or wait up-date to this post.
Until I find exact optical power data for Webb, let`s take Keck`s optical magnification of 17.500x and divide 1400 ly with 17.500. We should be able to see 1400 ly / 17.500 = 88.537.508 AU or how Kepler 452b looked like before 0.08 year or one month.
If Webb has the 288.000 optical power than we should see Kepler 452b like it is 0,00486 year or 1.7 day ago.
Have in mind that we are talking of infrared imaging not visual. Every other spectrum than visible must be properly translated. I mean, heat signature is not the picture of the object. It is just the heat signature of the object. From that we must extract how the image real looks like.
My question: does telescope zooms on true or apparent image? If it zooms on true image then we will have almost accurate representation from the time perspective. If it zooms on the apparent image, the light that is 1400 years old in our Kepler 452b case, then we actually have no enlargement in chronological sense but only image quality sense or optical resolution.
1400 ly minus 1.5 million km is real approach with chronological equivalent. Both are insignificant without optical zooming.
If we are zooming apparent image then we will need to send spacetelescopes to travel the desired direction even more, much more since 1.5 million km is nothing in astronomical terms.
The angular (optical) magnification is the ratio between focal lenght of an objective lens or primary mirror and focal lenght of the eyepiece. In astronomy we say angular, instead optical like in ordinary photography, because the sizes of celestial distances and objects are given in terms of their angular diameter as seen from the Earth.
Hubble`s telescope primary use was for gathering electromagnetic radiation from the UV and visible spectrum only. Infrared sensor was added later. Joined wavelenght is ranging from 0.1 to 2.5 microns, particularly: 0.1 - 0.4 UV and 0.4 - 0.7 visible light, 0.7 - 2.5 infrared.
This is good EM diagram:
New NASA space telescope James Webb will have magnification power of ????? with second major difference that it has much better and originally implanted infrared sensor. Infrared spectrum covers 1 - 1000 microns (0.001 - 1 millimeter). Webb goes to 28.5 microns which is near to mid IR spectrum. For comparison, Herschel (ESA space telescope named after discoverer of IR spectrum) observed from 60 to 500 microns or mid to far IR spectrum.
Hercshel and Webb observe(d) Universe before the visible light was created peering deep and deeper into the thermal traces of the Big Bang.
Another major difference is location: Hubble orbits the Earth at about 547 km. Webb will be positioned at L2, 1.5 million km from Earth following it in the orbit around the Sun, just like Herschel was. This location balance gravity effects between Sun and the Earth, reducing fuel consumption and also enabling telescope to block heat interference from the previously mentioned sources hiding behind Earth and using large, tennis court size sunshield.
Both Webb and Hubble telescopes are NASA & ESA collaboration. Herschel was ESA solely.
Sources:
Short history of telescopes: telescope is invented in 1608. by Lippershey, eyeglass maker, with further improvements by Galileo, Kepler, Huygens and Newton. There are two main kinds: refracting or Keplerian model (change direction when it enters at an angle) and reflective or Newtonian model (capable of reflecting light or other radiation). Refracting has one or more objective lens(es) in front and then tube with eyepiece for the focus at the end. Reflective has a mirror, usually even two, and an eyepiece for the focus at the end. In both cases eyepiece is convex lens which serves to collect refracted or reflected light.
(to be continued as soon as I find something about Webb`s optical power...)
I wonder can we actually see aliens with our telescopes. Why do I ask this question? Because light from distant objects travels very long to reach us. Let us take in the consideration exoplanet Kepler 452b which is aprox. 1400 ly from Earth. We can use anything distant for this purpose. At the present moment we see it as it was 1400 years ago. Therefore we must wait 1400 years to see how it looks now. Or we can use something which is called optical magnification.
I have found data for Earth`s best magnification telescope: Keck 17500x.
Others fall much behind: Subaru 7500x, Yale 4850x, Hubble 2880x, etc.
I can not find Webb optical magnification power nor focal lenght of its eyepiece. The only fact I found is comparison with Hubble stating that Webb can see 10 to 100 times better. I guess it means that it has 28.800 to 288.000 optical power. Please correct me here or wait up-date to this post.
Until I find exact optical power data for Webb, let`s take Keck`s optical magnification of 17.500x and divide 1400 ly with 17.500. We should be able to see 1400 ly / 17.500 = 88.537.508 AU or how Kepler 452b looked like before 0.08 year or one month.
If Webb has the 288.000 optical power than we should see Kepler 452b like it is 0,00486 year or 1.7 day ago.
Have in mind that we are talking of infrared imaging not visual. Every other spectrum than visible must be properly translated. I mean, heat signature is not the picture of the object. It is just the heat signature of the object. From that we must extract how the image real looks like.
My question: does telescope zooms on true or apparent image? If it zooms on true image then we will have almost accurate representation from the time perspective. If it zooms on the apparent image, the light that is 1400 years old in our Kepler 452b case, then we actually have no enlargement in chronological sense but only image quality sense or optical resolution.
1400 ly minus 1.5 million km is real approach with chronological equivalent. Both are insignificant without optical zooming.
If we are zooming apparent image then we will need to send spacetelescopes to travel the desired direction even more, much more since 1.5 million km is nothing in astronomical terms.
The angular (optical) magnification is the ratio between focal lenght of an objective lens or primary mirror and focal lenght of the eyepiece. In astronomy we say angular, instead optical like in ordinary photography, because the sizes of celestial distances and objects are given in terms of their angular diameter as seen from the Earth.
Hubble`s telescope primary use was for gathering electromagnetic radiation from the UV and visible spectrum only. Infrared sensor was added later. Joined wavelenght is ranging from 0.1 to 2.5 microns, particularly: 0.1 - 0.4 UV and 0.4 - 0.7 visible light, 0.7 - 2.5 infrared.
This is good EM diagram:
New NASA space telescope James Webb will have magnification power of ????? with second major difference that it has much better and originally implanted infrared sensor. Infrared spectrum covers 1 - 1000 microns (0.001 - 1 millimeter). Webb goes to 28.5 microns which is near to mid IR spectrum. For comparison, Herschel (ESA space telescope named after discoverer of IR spectrum) observed from 60 to 500 microns or mid to far IR spectrum.
Hercshel and Webb observe(d) Universe before the visible light was created peering deep and deeper into the thermal traces of the Big Bang.
Another major difference is location: Hubble orbits the Earth at about 547 km. Webb will be positioned at L2, 1.5 million km from Earth following it in the orbit around the Sun, just like Herschel was. This location balance gravity effects between Sun and the Earth, reducing fuel consumption and also enabling telescope to block heat interference from the previously mentioned sources hiding behind Earth and using large, tennis court size sunshield.
Both Webb and Hubble telescopes are NASA & ESA collaboration. Herschel was ESA solely.
Sources:
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hubblesite.org
Hubble vs. Webb - NASA Science
Overview In 1675, famed physicist and mathematician, Isaac Newton, penned a letter to his contemporary and rival, polymath Robert Hooke. In that letter, Newton wrote what would become one of his most famous remarks: “If I have seen further, it is by standing on the shoulders of giants.” Over...
www.jwst.nasa.gov
Short history of telescopes: telescope is invented in 1608. by Lippershey, eyeglass maker, with further improvements by Galileo, Kepler, Huygens and Newton. There are two main kinds: refracting or Keplerian model (change direction when it enters at an angle) and reflective or Newtonian model (capable of reflecting light or other radiation). Refracting has one or more objective lens(es) in front and then tube with eyepiece for the focus at the end. Reflective has a mirror, usually even two, and an eyepiece for the focus at the end. In both cases eyepiece is convex lens which serves to collect refracted or reflected light.
(to be continued as soon as I find something about Webb`s optical power...)
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