Tag: spiral

A dying star weaves a spiral in the night

By Phil Plait | October 10, 2012 11:01 am

The number of ways stars can find to die bizarre deaths will never cease to amaze me.

Some explode, supernovae which blast radiation across the Universe. Others fade away slowly over hundreds of billions of years, longer than the cosmos has been around. Some blow off winds of gas and dust, taking on strange shapes from perfect spherical shells to elongated structures that look like two jellyfish kissing.

And then some – a very few – are like R Sculptoris, a red giant on the thin hairy edge of death. And its death is both spectacular as well as just plain old damned weird.

Check THIS out:

This is not a drawing! It’s actual data, observations of R Sculptoris made using the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA looks at light far too low energy for our eyes to see; it’s actually out past infrared in the spectrum. Cold dust and gas emits light at this wavelength, including carbon monoxide. That molecule is created copiously in red giants and shines brightly in the submillimeter, making it easy to see with ‘scopes like ALMA. That’s nice, because CO can be used as a tracer for other, harder to detect molecules like hydrogen. Looking at CO really tells you a lot about what’s going on in the gas and dust.

And what’s going on? Ah, this is the really cool part.

When a star like the Sun (either a bit less massive, or up to about 8 times as massive) ages, the core heats up, which causes the outer part of the star to expand (like a hot air balloon), turning it into a red giant. The details are complicated – read this post on a similar star where I explain it in more detail (and you want to because the details are awesome) – but the bottom line is that helium builds up in a thin shell outside the star’s core, where it fuses into carbon. The fusion rate is insanely sensitive to temperature, and periodic imbalances in temperature cause vast and very sudden increases in the fusion rate – and by sudden I mean over a timescale of just a handful of years, the blink of an eye to a star. Called a thermal pulse, this huge fireball of energy is dumped into the star’s interior, blows upward like a tsunami, and then blasts material clear off the star’s surface.

The result is an epic paroxysm which blows out a massive wave of material, expanding in a sphere around the star. We’ve seen this before, like in the star U Cam. After a few years, you get an eerie detached shell of expanding material, like a smoke ring trillions of kilometers across.

OK, so that’s the thin shell thing on the outside. So what’s the deal with R Sculptoris that makes that freaky inner spiral pattern?

Read More

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Another spiral "UFO" lights up the sky. And it IS a spaceship.

By Phil Plait | June 12, 2012 6:48 am

Last week, over the Middle East, people were shocked to see a bright fan of light moving across the sky, which suddenly turned into a gigantic glowing spiral! This is not just some uncorroborated eyewitness story; there’s video:

http://www.youtube.com/watch?v=Iqifhg8NU8A

Pretty cool, huh? People are claiming it’s a spaceship… and they’re right. But it’s not an alien spaceship. It’s from Russia.

This has been positively identified as a Russian rocket booster, a Topol ICBM. In fact, this isn’t even the first time a Topol has been seen doing this! The last one was in December 2009, over Russia itself. And it happened even before then, a day before, over Norway, when a ginormous spiral lit up the sky and freaked the hell out of people (and the Internet). A SpaceX Falcon 9 booster did the same thing over Australia in June 2010, for that matter.

Basically, the booster is in space, where there’s very little or no air. It’s either leaking or blowing out fuel, which causes the booster to spin, and you get that amazing spiral water-sprinkler effect. I explain the whole thing in the Norway Spiral post.

That of course has not stopped the conspiracy theorists saying this is everything from a UFO to an interdimensional vortex. Ideas as breathless as they are silly popped up immediately. The truth is actually somewhat more mundane, but for a lot of people, that won’t even slow them down… and they’ll be all over the next one when this happens. That’s a conspiracy theory you can bank on.


Related Posts:

- Awesomely bizarre light show freaks out Norway
- Another Russian rocket spiral lights up the sky
- Oh, those Falcon UFOs!
- Followup: Falcon 9 spiral light video

Awesome death spiral of a bizarre star

By Phil Plait | September 6, 2010 10:44 am

I sometimes think I’ve seen everything there is in the sky, with nothing new left to see.

Then I get a rude — but welcome — wake-up call.

Check.
This.
Out.

hst_llpeg

[Click to enspiralnate.]

When I first saw this picture, my reactions, in order, were:

1) What the frak is that?

followed immediately by

2) This must be a fake!

But it’s not fake. It’s real, and it’s the dying gasp of a very, very strange star system.

The name of this thing is AFGL 3068. It’s been known as a bright infrared source for some time, but images just showed it as a dot. This Hubble image using the Advanced Camera for Surveys reveals an intricate, delicate and exceedingly faint spiral pattern. It’s so faint no one has ever detected it before!

So what’s going on here? First off, this is not a spiral galaxy! Read More

CATEGORIZED UNDER: Astronomy, Pretty pictures
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