Direct Imaging Oort Cloud objects requires 100 billion times better telescopes

The most distant galaxies can be seen by our telescopes but smaller and closer objects in the Oort clouds cannot be seen. The Oort cloud objects are too faint to see with the James Webb Space Telescope, but it should be able to see bright galaxies and quasars even at 13 billion light years.

James Webb Space Telescope (JWST) will have a magnitude limit of something like 30th AB magnitude at red and near-infrared wavelengths. It turns out that quasars at Z~10 can have brightnesses that enable them to be detected at these magnitudes and brighter.

In the near infrared, the Sun has an apparent magnitude of around -27.5. This means that the Oort cloud object would have a near-infrared apparent magnitude of 41 and would thus be 11 magnitudes too faint to be seen by JWST. This was based on estimation with a big object that was as close as an Oort cloud object is expected it to be and gave it a high albedo.

Detecting Oort cloud dwarf planets would likely take a space telescope with an 11 kilometer mirror.

14 meter mirror instead of Webb 6.5 meter

The Large UV/Optical/Infrared Survey (LUVOIR) is a proposed multi-wavelength observatory with the ability to characterize exoplanets, study galaxy formation and evolution, and examine the early universe. It will have a primary mirror of 30 to 45 feet (9 to 14 meters).

As currently proposed, LUVOIR could probe star-forming regions of distant galaxies and map the distribution of dark matter in the nearby universe. It would be capable of identifying the first starlight in the early universe and image the icy plumes spouting from Saturn’s icy moon Enceladus and Jupiter’s giant moon Europa. The Earth-orbiting instrument should resolve features as small as 125 miles (200 km) on Pluto and other Kuiper Belt objects.

Astronomers would be able to use LUVOIR to analyze the atmospheres of Earth-like worlds around sun-like stars, hunting for signs of life.

A large telescope like LUVOIR, combined with a coronagraph to block the light from the star, should be an enormous improvement over smaller telescopes. Over average observations, a 4-meter telescope should be capable of spotting something like six Earth-candidates, she said, while an 8-meter instrument could spot only around 25. A 16-meter instrument with a coronagraph should reveal around 100 worlds.

In 2015, Spiderfab was presented at the Future in space Operations workshop.

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>Higher Power, Resolution, Sensitivity and Bandwidth
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SOURCES – Tethers Unlimited, FISO, NASA,

8 thoughts on “Direct Imaging Oort Cloud objects requires 100 billion times better telescopes”

  1. One of the things that cracks me up. We literally could have dozens of giant alien ships in our solar system and not even have a clue. Maybe we are like a soap opera

    Reply
  2. One of the things that cracks me up. We literally could have dozens of giant alien ships in our solar system and not even have a clue.Maybe we are like a soap opera

    Reply
  3. One of the things that cracks me up. We literally could have dozens of giant alien ships in our solar system and not even have a clue. Maybe we are like a soap opera

    Reply
  4. One of the things that cracks me up. We literally could have dozens of giant alien ships in our solar system and not even have a clue.Maybe we are like a soap opera

    Reply
  5. One thing’s for sure… the calculations for the brightness of a 20 km diameter more-or-less Lambertian (uniform reflectance across whole hemisphere of emission), medium albedo object at 2,000 AU was off by a few factors… but in the end, not terribly off. At Earth, albedo 0.35, 20 km diameter, 2,000 AU distance object will reflect ONE photon into the opening of the James Webb scope (6.5 m diameter) about every 3.5 days. One photon. It would take an awfully long time to build up an image. Even if you knew exactly where to point the JWT. Just saying. (I wish the original authors had gone thru the “photons per second” part, it makes it so much more palpable how dim the thing is.) Anyway, If we had a 5,000 m full-filled space scope (i.e. friggin’ ridiculously large), the photon rate bumps up to near 2 photons per second. You really could build up an image in fraction of an hour. And at 1000 nm wavelength (near infrared), 1.24 eV IR would focus on a near-perfect 5,000 meter scope to image features as small as 73 km, at 2000 AU. So… after all that, the image of the Oört object will STILL be just a somewhat fuzzy blob. Darn. This is why we send probes. They get much closer. And send back brilliant pictures. We like probes. A lot. Just saying, GoatGuy

    Reply
  6. One thing’s for sure… the calculations for the brightness of a 20 km diameter more-or-less Lambertian (uniform reflectance across whole hemisphere of emission) medium albedo object at 2000 AU was off by a few factors… but in the end not terribly off. At Earth albedo 0.35 20 km diameter 2000 AU distance object will reflect ONE photon into the opening of the James Webb scope (6.5 m diameter) about every 3.5 days. One photon. It would take an awfully long time to build up an image. Even if you knew exactly where to point the JWT. Just saying. (I wish the original authors had gone thru the photons per second”” part”” it makes it so much more palpable how dim the thing is.)Anyway If we had a 5000 m full-filled space scope (i.e. friggin’ ridiculously large) the photon rate bumps up to near 2 photons per second. You really could build up an image in fraction of an hour. And at 1000 nm wavelength (near infrared) 1.24 eV IR would focus on a near-perfect 5000 meter scope to image features as small as 73 km at 2000 AU. So… after all that the image of the Oört object will STILL be just a somewhat fuzzy blob. Darn.This is why we send probes. They get much closer. And send back brilliant pictures.We like probes.A lot.Just saying””GoatGuy”””””””

    Reply
  7. One thing’s for sure… the calculations for the brightness of a 20 km diameter more-or-less Lambertian (uniform reflectance across whole hemisphere of emission), medium albedo object at 2,000 AU was off by a few factors… but in the end, not terribly off.

    At Earth, albedo 0.35, 20 km diameter, 2,000 AU distance object will reflect ONE photon into the opening of the James Webb scope (6.5 m diameter) about every 3.5 days. One photon.

    It would take an awfully long time to build up an image. Even if you knew exactly where to point the JWT. Just saying. (I wish the original authors had gone thru the “photons per second” part, it makes it so much more palpable how dim the thing is.)

    Anyway, If we had a 5,000 m full-filled space scope (i.e. friggin’ ridiculously large), the photon rate bumps up to near 2 photons per second. You really could build up an image in fraction of an hour. And at 1000 nm wavelength (near infrared), 1.24 eV IR would focus on a near-perfect 5,000 meter scope to image features as small as 73 km, at 2000 AU.

    So… after all that, the image of the Oört object will STILL be just a somewhat fuzzy blob. Darn.

    This is why we send probes.
    They get much closer.
    And send back brilliant pictures.
    We like probes.
    A lot.

    Just saying,
    GoatGuy

    Reply

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