I Didn’t Know a Star Could Move that Fast….

I hardly ever get to do math. Mind you, this isn’t real math, but it involves large numbers, a white dwarf and a black hole.

I’ll start here: Science Daily just announced that a team from Michigan State University using NASA’s Chandra X-ray Observatory, NASA’s NuSTAR, and the Australia Telescope Compact Array, have apparently found a white dwarf orbiting a black hole.

That’s not necessarily news if that was all there was to report, but the key finding is that the distance between the white dwarf and the black hole is only about two and a half times the distance between the Earth and the Moon.

I’ll let that set in. A star is hanging out within spitting distance of a black hole. And, the star hasn’t fallen into the black hole’s event horizon yet. The team from Michigan State believes that the star won’t fall in anytime soon.

How can that be?

Answer: The star apparently makes one full orbit every 28 minutes.

Yes, it’s orbiting VERY fast — like more than 8 million miles/hour fast.

So, I promised math.

* Average Distance from Earth to Moon = 239,228 miles
* Two and one-half times that distance (which is the distance between the dwarf and the black hole) = 598,070 miles
* Circumference of a circle = C = 2 π r
* Thus the orbit of the dwarf around the black hole is = 2 π (598070) = 3.76 million miles
* If the dwarf travels that distance in 28 minutes, then it’s speed is greater than 8 million miles/hour.

That’s just astounding.

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