0 upvotes, 1 direct replies (showing 1)
View submission: What was this object
You are both partially correct. First, humans judge an object's speed based on angular rate-of-change and estimated distance. Humans suck at estimating distance. (This is a significant factor in UFO eye witness testimony.)
Comets dropping in from the Kuiper Belt typically cross Earth's orbit at speeds in excess of 25k kps. Comets that originate farther out can be going much faster.
A comet at the same distance as the Falcon 9 in the video would appear to cross the sky much faster and be much brighter as its outer layer burned off in the atmosphere. The rest would depend on its mass.
A small one would burn up just like hundreds of meteors do every day and not likely to survive such a close approach. A larger one that was farther out could look about the same from our POV without ever entering the atmosphere.
A comet large enough to cause serious damage would be visible to even amateur astronomers like myself months in advance at night and possibly during the day in the final few weeks of its approach.
Hope that helps.
Comment by Quirky_Box4371 at 03/07/2024 at 13:46 UTC
1 upvotes, 1 direct replies
How am I partially correct? Mathematics minor here. How humans judge distance has nothing to do with the gravitational effects felt by the comet. A few quick (2)(Pi)(r) calculations and then using the time constant to deduce velocity is all you need. With a comet at say a few million miles (very close pass and would look far larger than this), and the rocket at 100 miles (r), I believe you will also find the object would exceed the escape velocity of the Sun. Bye Felicia to Mr. Comet, neither Earth or it would barely notice due to the velocity and distance. There's no reason to involve atmospheric effects as this is not a meteor discussion, and most comets are actually dozens of millions of miles away. Halley as an example, looked similar in size to this.