What if Earth had no moon? Why can’t we direct a telescope to see if we actually did land on the moon?

SECOND QUESTION FIRST (it actually sounds useful)

(*) light year = 6 trillion miles; ten light years is 60 trillion miles, or 240 million times as much as 1/4 million miles)

(**the nearest star is four light years away, but the nearest galaxy is a couple hundred million light years off)

The necessary magnification to see the moon’s surface with one meter resolution, from near earth orbit or about a quarter million miles away, is orders of magnitude beyond what the Hubble Space Telescope can achieve. Proof left to the reader, but that happens to be a fact. With one meter resolution you could make out a grainy image of something *possibly* identifiable as a lunar lander. But the Hubble can’t get nearly that fine-grained a picture from a quarter million miles away. A Star ten light-years distant (*) is fine – but then its size is a lot more than 240 million meters (i.e. about 150 thousand miles.) Our sun is more like 864 thousand miles wide. The resolution needed to barely make out our moon vehicle from Hubble orbit would give us a picture of a star the size of our sun that is just ten light years away (**) about seven pixels wide. Doesn’t sound like much, but it’s huge – it would consist of about 39, or pi x 49/4, pixels. For comparison, thats the size of a small emoticon. Photographic plates that include a small-emoticon-sized image of a nearby star don’t exist.

FIRST QUESTION:

Without any moon the earth’s orientation relative to the sun would wobble. For a while the north pole might be in direct overhead sunlight at the summer solstice, about like our equator’s view of the sun, but worse – think of the sun over the equator, but 24×7. Six months later the south pole would be in permanent day because the earth would be on the other side of the sun.

That’s just one possibility – the earth’s axis would wobble. A lot. Just the way it works. All of the other possible scenarios have equal likelihood, on a timeframe too short for any kind of life to proceed past the single-celled stage.

To make it worse, the earth’s magnetic field works OK because its tilt relative to its axis around the sun is only 23 degrees; the magnetic field keeps the solar wind from blowing our atmosphere away. Mars wasn’t so lucky, and Venus is somehow stuck with so much CO2 there has to be some other factor that keeps it in place. Perhaps the solar wind can’t budge it. Regardless, it’s not going anywhere.

But the earth’s magnetic field would be end-on to the sun as often as sideways. earth’s atmosphere would become like Bob Dylan’s answer, “blowing’ in the wind.” The solar wind.

Gone.

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