Editing 1231: Habitable Zone
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*The telescopes used for this type of research are designed to view faint, distant objects. In the images that they produce, objects the size of telescopes are not visible. Therefore, the astronomer would not see the reflection of the telescope. | *The telescopes used for this type of research are designed to view faint, distant objects. In the images that they produce, objects the size of telescopes are not visible. Therefore, the astronomer would not see the reflection of the telescope. | ||
*The telescopes have a motor that moves them to compensate for earth's rotation, so that they stay pointed on the same part of the sky. This means that the telescope would not stay pointed at the mirror. The prankster would have to move the mirror in a very precise way to maintain the illusion. | *The telescopes have a motor that moves them to compensate for earth's rotation, so that they stay pointed on the same part of the sky. This means that the telescope would not stay pointed at the mirror. The prankster would have to move the mirror in a very precise way to maintain the illusion. | ||
| β | *For the astronomer to have ascertained that the planet is in a star's habitable zone means that the astronomer observed the planet to be the size of Earth and observed the distance between the planet (Earth) and its star (the Sun), and the approximate size of that star. However, in a mirror at any reasonable distance from the | + | *For the astronomer to have ascertained that the planet is in a star's habitable zone means that the astronomer observed the planet to be the size of Earth and observed the distance between the planet (Earth) and its star (the Sun), and the approximate size of that star. However, in a mirror at any reasonable distance from the earth, up to several times the distance of the moon, the earth would appear to be larger than the sun. |
| β | *For the relative sizes of the | + | *For the relative sizes of the earth and sun to be correct in the reflection, the mirror would have to be as far from earth as the mirror was from the sun. But even pointing to a mirror at a distance of the moon would require a real huge one, probably more than one hundred kilometers (sixty miles) in diameter. |
*A professional astronomer should be able to realize nearly instantaneously that they're not looking at an Earth-like, extrasolar planet (as should anyone, in fact, who is familiar with even the basic arrangement of Earth's continents and oceans), but instead Earth itself. | *A professional astronomer should be able to realize nearly instantaneously that they're not looking at an Earth-like, extrasolar planet (as should anyone, in fact, who is familiar with even the basic arrangement of Earth's continents and oceans), but instead Earth itself. | ||
*A telescope of this size, or indeed any one employing a solid mirror rather than a massive disk of dust in space, could never see an extrasolar planet with this level of detail without insurmountable engineering issues. | *A telescope of this size, or indeed any one employing a solid mirror rather than a massive disk of dust in space, could never see an extrasolar planet with this level of detail without insurmountable engineering issues. | ||
