RE: Whats the speed of Dark ?

Sorry, I didn’t finish what I meant to say about tidal forces.

The density of an object determines the so called tidal forces.

Tidal forces is merely the change in gravitational force over distance.

A super giant star like Beetlgeuce (spelling) if placed in our solar system would have its outer surface at about the orbit of Jupiter.

In other words it is rather large.

It is not however very dense… (obviously with such volume)
Its change in gravity is similar to Earths in that the difference in gravity over 1.5-2m (ie head to feet) is not noticible.
If it were to collapse to become a neutron star however things would be very different. Its density would change from roughly the same as syrup to hundreds of thousands of tons to millions of tons per teaspoon full… if you had a cup of it on earth in your hand (even ignoring the temperature and pressure) the cup would plunge down to the core of the earth and the earth might move a few cms up to meet it too!
If you were in a spaceship orbitting this neutron star you would not be very happy… the difference in gravity between you head and your feet might be 100g or even 1000g… ie fatal.

Ironically this applies to black holes too.
Although matter is completely destroyed by the infinite gravity of the singularity and therefore there is not very much mass inside most Black Holes as matter enters the hole gets bigger based on the amount of mass that enters it.

A 2.5cm black hole of the same mass as the Earth whizzing through our solar system on a collision course with earth.

Warnings might include planets orbits being influenced by this tiny earth, or asteroids disappearing or being nudged out of orbit.

When it finally reaches earth it will take some time to destroy it… like draining a pond through a plughole.
Energy will be released as matter heats up as it is crushed together as it passes the event horizon.
The black hole now with the adition of the mass of the earth will be slightly larger… say 2.8 or 3.0 cm across and now twice as massive.
The effect on the black hole’s path would be similar to that of two earths collideing but without the explosion and fragments and debris.

With the technology of star trek we might be able to save ourselves… but not with their phasers or photon torpedos… with the technology that allows the crew to stand upright in apparantly 1g in space…