# Weird white dwarf pulsar baffles boffins as its pulsating pattern changes over decades

Scientists trying to crack the mystery behind the fastest-pulsating white dwarf have found that its brightness levels change over a timescale of decades. AR Scorpii is a distant, peculiar binary star system located 380 light years away. It’s made of a collapsed white dwarf star circling its larger red dwarf companion. It was …

1. #### AR Sco

Snigger. That is all.

2. #### Proving that whenever you think you've reached the limit of how strange the universe is

It gets a bit stranger.

It's not quite the "On off star" of "A Deepness In The Sky" but it's quite odd.

So thumbs up for analysing the data and getting this result.

1. #### Re: Proving that whenever you think you've reached the limit of how strange the universe is

Yes, as Isaac Asimov is reputed to have once said, "The most exciting phrase to hear in science is not 'Eureka!' but rather, 'hmm... that's funny...'"

3. #### a teaspoon ... would weigh 15 tons.

Surely, that would depend where you weigh it. If you weighed it *here* it might weigh 15 tons, but if you weighed it where you got it, it'd probably weigh a damn sight more...

1. #### Re: a teaspoon ... would weigh 15 tons.

It won't matter. A properly calibrating "weighing machine" gives you the mass of the object being weighed.

But, obviously, if you use a balance calibrated for earth if will give a silly answer. And there are various caveats about relativity and non-inertial frames.

I'll leave you to write your own jokes.

1. #### Re: a teaspoon ... would weigh 15 tons.

> if you use a balance calibrated for earth

Well, actually, if you use a balance and always use the same standard weights (masses - yes yes we know they're different things, especially outside of a 1g field) on one side of the balance, it will register the same weight/mass no matter where you use it.

Your bog-standard springy scale, on the other hand, is another story entirely.

2. #### Re: a teaspoon ... would weigh 15 tons.

Weigh is the wrong word, especially here. It should be 'has a Mass of 15 tons' mass doesn't need a gravity well, weight does.

1. #### Re: a teaspoon ... would weigh 15 tons.

If you're trying to measure mass, use the right units: newtons.

Tons, whether American, British or metric, are measurements of the force exerted by gravitational attraction at the Earth's surface.

</pedant>

1. #### Re: a teaspoon ... would weigh 15 tons.

You have those slightly completely reversed though

https://en.wikipedia.org/wiki/Mass_versus_weight

2. #### Re: a teaspoon ... would weigh 15 tons.

> If you're trying to measure mass, use the right units: newtons

Oops: 100% wrong.

Kilograms for mass; Newtons for weight.

1. #### Re: a teaspoon ... would weigh 15 tons.

Never mind science - what would in weigh in el Reg units?

2. #### Re: a teaspoon ... would weigh 15 tons.

Well that is assuming that inertial mass is equivalent to gravitational mass. I always was uncomfortable about that myself; I have quite a large gravitational mass (compared to most skinny buggers) but my inertial mass is amazing when the wife asks me to cut the grass or do the washing up.

Mind you, when it comes down to software or other such matters my inertial mass makes a feather look like a lead cannonball.

4. #### Learn something every day

I knew white dwarfs, today I've learned about red dwarfs. They can last trillions of years because they are convective, meaning they don't build up helium in the core.

Science. You can read about for thirty years but there's always something to surprise you.

1. #### Re: Learn something every day

I'm not sure space is expected to last trillions of years, let alone stars.

1. #### Re: Learn something every day

It depends on whether you believe in continuous expansion or a big bang followed by a big crunch. If the first, the universe will get bigger, things in it will get more isolated, and stars will run down until eventually everything fades to black. If the latter, the red dwarves will collapse back into the singularity before they run out of fuel.

I do not expect to be around to find out for certain which will happen, though.

2. #### Re: Learn something every day

Might be a lot longer than trillions

https://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe

5. My theory is that it's likely to be a star surrounded by pre or post planet debris that is coalescing into larger blobs causing the light to be stronger when they're more organised and then they bash into each other every so often splitting up scattering the light, then they coalesce again. So, we're observing a brightening and dimming effect as the light/radiation is obscured/scattered and then picks up again, depending on how organised the debris is at any given time.

It would make sense to me that solar systems would go through long periods of stuff coming together and bashing into each other and splitting apart until eventually the only objects that survive are ones with clear paths and you get an organised, non-chaotic solar system like ours.

It's also quite possible that loose debris (in huge quantities) could do something like that very quickly. It could be just balls of rubble / dust coming together then smashing apart in a matter of a few years.

6. #### Not much change since Iain Thomson's remarkably similar article on 8 Feb 2017.

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