Dying Star Weaves a Trillion-Mile-Wide Spiral In the Sky 46
The Bad Astronomer writes "Using the newly-commissioned ALMA radio observatory, astronomers have taken detailed images of one of the most amazing objects in the sky: the red giant R Sculptoris (abstract). As the star dies, it undergoes gigantic seizures beneath its surface that blast out waves of gas and dust from the surface. These normally expand into a spherical shell, but the presence of a nearby companion star changes things. The combined orbits of the two stars fling out the material like a garden sprinkler, forming enormous and incredibly beautiful spiral arms. Measuring the size and shape of the spiral shows the last eruption was 1800 years ago, lasted for nearly two centuries, and expelled enough material to make a thousand earths."
Re:older than itself (Score:4, Informative)
Is it just me or does that not make sense?
The universe is a little younger than 14 billion years old. If it takes a hundred billion years for a star to fade away, that's six times the length the universe has existed up to this point.
trillions and trillions (Score:5, Informative)
I can't do Libraries of Congress for linear distance, but I think there's something better than a trillion miles.
So I asked Google for "1 trillion miles in au". An astronomical unit (1 AU) is the Sun-to-Earth orbit's average radius. I forget how many miles that is, and that's kind of the point.
1 trillion miles = 10757.8002 Astronomical Units
To put that in perspective, Earth is in a middle ring of our solar system. Pluto is way out there. I ignored other far-flung rocks like Xena or Gabrielle or whatever they're calling them these days.
Google's Calculator doesn't memorize "radius of pluto's orbit in au" but on the Pluto Fact Sheet [nasa.gov] I found Semimajor axis (AU) 39.48168677.
Diameter of our solar system is then ~80 AU. I did look up the heliopause for a farther "edge of our solar system, and got Starting in May 2012 at 120 AU, Voyager 1 detected a sudden increase in cosmic rays, an apparent signature of approach to the heliopause.. Both are miniscule compared to ~10800 AU for this article's celestial feature.
I remembered that the nearest neighbor star is roughly 4 light years away. Let's not quibble about precision, one digit is enough.
4 light years = 252,958.905 Astronomical Units
Re:Enough material to make a thousand earths. (Score:5, Informative)
one meter is equal to one ten-millionth of the length of the Earth's meridian along a quadrant through Paris.
And the old definition of a gram was:
the absolute weight of a volume of water equal to the cube of the hundredth part of the meter, at the temperature of melting ice.
So technically our measurement for length is based on the size of the earth. And our measurement for mass is based on our measurement for length and there-by indirectly based on the size of the earth. So using the earth as a unit of measurement is perfecting in line with the metric system. Even if we have, in recent years refined those measurements using light waves and such so we can apply them to nonsense like atoms.
I guess I'm nitpicking, but so are you