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How much of the visible universe have we explored?

  1. Apr 5, 2014 #1
    I'd like to know how much of the visible universe we've physically explored. Either with space probes, rovers or in person.

    I know we have a probe around every planet in our own solar system? So given the amount of galaxies, planets our there ect how much of the visible universe have we explored? As a percentage?
  2. jcsd
  3. Apr 5, 2014 #2


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    If you were to be very generous with labeling what we've explored so far, and take the volume of a sphere with the centre at the Sun and the radius equal to how far Voyager 1 has reached(about 125 AU), it would encompass the volume equal to 0.032 cubic light-years.
    The observable universe's radius is estimated at about 45 billion light years, so its total volume would be 3.7*10^32 cubic light years, or 37 with 31 zeroes.
    This makes our solar system as 'explored' by Voyager be a whooping 0.00000000000000000000000000000001 percent of the observable universe.

    But, as mentioned earlier, it's a very generous number. We don't have probes around every planet. We had probes fly by every planet, if that counts. We've landed probes on just a few, and they rarely remained operational for long.

    Bottom line: Earth is a tiny speck in the mind-boggling vastness of space.

    Have a look at this NASA page about Solar System exploration:
    It lists all the missions so far.
    Last edited: Apr 5, 2014
  4. Apr 27, 2016 #3
    With physical probes we have only explored the solar system, the voyager spacecraft (whose main task was a flyby of planets) are still closer to the Sun than any other star.
    Rovers have only gone to the Moon and Mars, there have been a number of static landers on Mars too, and some on Venus, one on Titan.
    The planets and their moons have now been studied (less so for Uranus and Neptune) by orbiters and flyby missions,and some comets and minor planets have as well.
    However as well as physical probes, there have been great advances in telescopes over the last century, Hubble being the best example.
    Humans have only gone to the Moon, and only for a few days each time.
    The amount of observable space explored by human explorers (other than on Earth) is not much above zero,
    Last edited: Apr 27, 2016
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