We’re about to watch a star almost dive into the Milky Way’s black hole

The new GRAVITY instrument will allow scientists to closely the study the star, S2.

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[Dilbert]

Gooberslot[/url]":leucl6km]Can they predict when the star will actually fall into the black hole?

It won't fall in in the short term. After all, that star must be very old by human timekeeping standards and it's been orbiting this entire time. Long term, many millions or billion years the star may lose its orbital momentum due to exchange of gravity waves, or due to drag if there's gas or other matter in its path. We'd need rather precise measurements of the change in its orbit, orbit after orbit, to determine that. We just recently begun to track this star. Our instruments will no doubt get better from here, and our data more accurate. But at this time there's no way to know for sure. That's okay. We don't know everything. We can make a pretty good assumption, however, that we will keep learning more, and someone some day will find out.

 

[Dilbert]

johnt007871[/url]":2invsleo]I'm going to assume this an alien super weapon that will eventually be sent hurdling toward their enemy.

You jest. But I'll give you a scientific answer anyway. The amount of energy required to fling this star out of its orbit and toward some faraway destination would be so staggering, just about any other solution would be less energy intensive. Gathering up gas and making a new star would make more sense than using this star!

Best cosmic impactors are those that require very little nudging to slightly alter their trajectory toward where you want them to go.

 

[Dilbert]

tpl[/url]":3h52279k]Will this or rather did this event 25998 years ago generate detectable gravity waves or a) our instruments are not yet sensitive enough b) the close encounter generates no such wave c) the 'frequency' of these waves would be too low for us to hear.

Yes, any two bodies orbiting each others common center of mass do radiate gravitational waves, but our instruments are far too weak to detect them at this time. Earth and sun radiate gravitational waves. It is a small amount of energy on the order of 200W which is a laughably small amount of energy when compared to the potential and kinetic energy of Earth's orbit around the sun.

That event of two massive black holes merging, creating gravitational waves, which was picked up by LIGO? That massive event changed the length of one of the LIGO's 4 Km vacuum tunnels by 1/10,000th of size of a proton. It's remarkable that our instruments can detect that, isn't it? Anything very much smaller and it would be undetectable.