u/Turbulent_Hippo_1546

In the last few days I read a post somewhere about what would happen if the sun disappeared. I have two questions.

When the sun's gravity disappears, the Earth would leave its orbit on a tangent. My question is this. Would that departure occur at the instant the sun vanishes or would it occur at the time we notice the disappearance, about 8 minutes later?

What would this do to the moon? Would the Earth Just drag it along or would it go off on a tangent by itself?

The government went to a lot of trouble to hollow out a part of Cheyenne Mountain for NORAD. If I recall correctly, much of it is a number of buildings on springs. I started to wonder what they did during construction to avoid some geological issues.

Groundwater would probably be the major issue ongoing. It has to be drained off somehow. And, based upon my limited knowledge of what comes out of old mines, the water would be very likely to be highly mineralized.

Time goes by. We no longer use the facility 5,000 years from now. Groundwater has been dripping and dripping for a very long time. Stalactites and stalagmites have developed. All of the buildings have collapsed because their springs corroded. The ruins are covered with the minerals.

Have we created a man-made version of Mammoth Cave? Or will some other geological event have cracked open the mountain?

I have seen it asked several times. What man-made geological changes would be visible after x number of years?

What geological features would be curious enough? I would first suggest huge open pit mines. A geologist in the future might wonder what caused the craters that do not appear to be volcanic or the result of a meteor. The mineralogy around the area of the crater versus the inside of the crater would also indicate something unusual.

A second candidate could be canals. You would need to have a canal that is clearly not an unusual water course. The Panama canal could be one. In my area, the Welland canal in Ontario might be another.

Finally, what is with all the radioactive hotspots all over the world? Everywhere that there is a nuclear power plant, there could be, in the future, a nuclear hotspot. They would be characterized by minerals and isotopes that are not native to the surrounding area, and levels of radioactivity that are not normal. Most of these hot spots would be found in the immediate vicinity of water, or where there had been water.

Does Mount Olympus cause Mars to wobble in its orbit? And, is there any possibility at all that the volcano is still active?

What spectacular geological events can be expected in the next 10 to 15,000 years?

I am favoring two. When Niagara Falls reaches Lake Erie, we will see an event similar to what opened the Mediterranean to the Atlantic or the Black Sea to the Mediterranean.

Kamaʻehuakanaloa Seamount emerging from the Pacific is my second choice. I am curious as to how long it will take from its initial emergency to the establishment of a permanent island.

An undersea collapse of Cumbre Vieja in the Canary Islands might qualify but it is not clear if it falls into my time frame.