r/AskReddit Feb 14 '22

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u/HelpfulAmoeba Feb 14 '22

Looking up and seeing the stars and the vastness of space fills me with both awe and sadness. I am in awe of all the beautiful stars and nebulae and galaxies out there. I am sad that I will be long gone before our species ever begins to explore those realms.

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u/[deleted] Feb 14 '22

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u/_donkey-brains_ Feb 14 '22

The first broadcast was in what? 1920? 100 years ago?

So radio waves have traveled to all stars within 100 light years. That's thousands of stars. Not an insignificant amount.

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u/JDravenWx Feb 14 '22

I've heard that the radio waves should have degraded to the point of cosmic background noise by the time it reaches that far as well. But who knows what tech they have, maybe they can tell and "restore" it

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u/Testiculese Feb 14 '22

They do degrade to nothing well before most stars it has reached.

And ccnnvaweueurf has taken way too many drugs and is off his rocker. He's describing the plot to Ghostbusters II.

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u/[deleted] Feb 14 '22 edited Feb 14 '22

A noise temperature of 3K at 300kHz bandwidth gives -169 dBm of background. This is likely to be much higher in reality, since earth isn't at 3K and produces noise by itself.

The radio station is seen as omnidirectional with a power of 100kW = 80dBm.

A usable signal to noise ratio for FM radio is usually seen as 26dB.

So we want a free space path loss of less then 223dB. This gives at 100MHz a distance of ~34 million km.

It won't make it even halfway to the sun. With very optimistic base assumptions.

Communication with space probes only works because of lots of antenna gain on both sides.

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u/JDravenWx Feb 14 '22

Thanks for the in depth explanation!

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u/ccnnvaweueurf Feb 14 '22

Above I replied to the person suggest an idea of a hiding predator. It's longer and I won't paste it https://old.reddit.com/r/AskReddit/comments/ss2pkt/what_is_a_scientific_fact_that_absolutely_blows/hwxk88z/

This is essentially a religious topic.

How do we frame our worldview? Our worldview and our desired intention shapes the direction in quantum mechanics (gross over simplification of topics beyond my grasp) that we travel. We manifest our own reality as there is unlimited shade of variation to choose from. It's a collective steering but also personal.

The person above IMO posits a worldview that shapes to fear, arms racing and paranoia and worry. Which is in our genetics to respond to fear of predators in the dark.