Supermassive black hole devours star and becomes X-ray flashlight

That's bloody clever

Nice one, boffins!

Very interesting

One minor point: tidal disruption (objects being ripped apart by a black hole) also occurs outside the event horizon (which is why we can observe it), due to the huge differential in gravitational pull between parts of an object closest to, and furthest from the black hole. It may well occur inside the event horizon, but we have no way of knowing it.

No black hole required

Nonsense. The X-rays are indisputable observation. The black hole nonsense is made up because you need something that big to exert sufficient gravitational pull to make x-rays.

Nature uses electricity to make x-rays, such as a lightning bolt. Dentists make x-rays using electricity, and not mechanically. Saturn emits xrays, Jupiter emits xrays. No black hole required.

Could dormant black holes be the Dark Matter we seek?

Discovery Channel Science

This article is a bit like a typical Discovery Channel science program - oversimplified, factually wrong in some respects and ultimately misleading.

"...a dormant black hole will awaken and start a feeding frenzy..."

Black Holes are neither dormant and nor can they 'awake' - this suggests a change in activity or a change of state of the BH. They are, like their name suggests, essentially a hole in space and any activity or dormancy occurs in the material around the BH, not in the BH itself.

"...if anything ventures past its event horizon..."

If anything ventures past the Event Horizon of a BH then any consequences are unobservable to us, or anyone else. Once again, the clue's in the name - events are not observable beyond the Event Horizon; we can only observe events occurring outside the EH.

Btw, the plural of 'spacecraft' is 'spacecraft'.

@AC: "Could dormant black holes be the Dark Matter we seek?"

A very small proportion could be but overall, no. BHs are formed from baryonic material and insufficient baryonic material was formed in the Big Bang to account for the total amount of Dark Matter required to explain what we observe. In addition, if all of the DM were in the form of BHs then the microlensing effects we see due to DM would have different characteristics.

Re: Dormant black holes are hard to detect

Well, DUH, they're black and always in the dark corners of the universe!