Speaking of solar storms causing gorgeous auroral displays…
In late October, a coronal mass ejection (CME) — a violent explosion of subatomic particles erupting from the Sun at high speeds — blasted away from our star, impacting the Earth, and setting off aurorae seen as far south as Arkansas. It was cloudy here in Boulder, but from space, the view is always clear. NASA’s STEREO spacecraft are twin machines, one ahead of the Earth, one behind, both staring at the Sun 24/7. They are currently roughly 100° around the Earth’s orbit, so they are essentially seeing the Sun "from the side".
STEREO A, ahead of the Earth in its orbit, captured images of the Sun during October’s solar hissy fit, and got dramatic footage of the explosion:
Yegads. [Make sure you click the HD button to see this in all its glory.]
The Earth is off to the left, well off-screen, in this animation. The Sun is blocked by a circular mask, so fainter things can be seen (its disk is represented by the white circle). The big CME occurred early on October 22 and is followed by others.
The energy and raw power of this event is staggering: a billion tons of matter was hurled away from the Sun at several million kilometers per hour. This completely dwarfs into nothing all of humankind’s energy output, and is vastly greater than the explosive yield of all nuclear weapons at the height of the Cold War combined.
And during its active phase, the Sun tosses these things off like a gourmand barely stifles a belch.
The danger to Earth from CMEs is real, if rare. A powerful one can generate strong electric currents in conductors (like power lines) on the Earth’s surface, which can cause widespread blackouts. They can also damage satellites in orbits or be a radiation danger to astronauts. In general, though, our magnetic field protects us on the ground, preventing us from suffering any direct danger. And, as a bonus, we can get beautiful displays of aurorae out of them. While they’re a concern for us as an electricity-using and space-faring race, we can protect ourselves from their danger while simultaneously reveling in their power and majesty.
Credit: NASA/GSFC/STEREO; Eric Hines
Related posts:
- Gorgeous aurorae
- The comet and the Coronal Mass Ejection
- The Sun blasts out a flare and a huge filament
- One solar piece of flare
November 3rd, 2011 at 11:56 am
What’s the diameter of the “red” part of the picture above?
November 3rd, 2011 at 11:56 am
There is a giant sunspot just coming into view. Already gave off some M flares. If we are lucky it’ll send off some more CME when it’s better aligned, we’ll get hit again and see some more auroras.
And if I’m really lucky the clouds will stay away!
November 3rd, 2011 at 12:52 pm
@1 DennyMo
That’s a loaded question there. What really matters is the angular size. Something which is farther away looks smaller. But looking at the Sun’s distance, the ratio of the solar diameter to the camera’s diameter is about 13. So the diameter which is seen at the Sun’s distance is ~18 million km.
November 3rd, 2011 at 3:04 pm
A CD of death!
November 3rd, 2011 at 5:14 pm
Upon seeing the blast, I was like “Whoa!”.
The Sun is truly awe inspiring.
And to heck with those that call it an “ordinary star”.
No such animal, far as I’m concerned!
November 3rd, 2011 at 8:35 pm
@ ^ Grand Lunar – agreed. You are in fact entirely correct there.
Our Sun is in the top 5% of stars mass and luminosity~wise with the vast majority of stars being very much smaller (only Jupiter sized in some cases) and fainter red dwarfs which make up 70% of all stars – although we cannot see a single one without optical assistence! Another 15% of stars are slightly brighter and more massive K type orange dwarfs such as Epsilon Eridani, Epsilon Indi and 61 Cygni.
Another 10% of stars – and ever rising – are white dwarfs which cram about a Sun to a Sun-and-a-half’s worth of mass into a sphere ranging from about the size of Neptune down to less than the radius of Earth* and thus because of tehir tiny size are very much fainter with not a one visible to unaided human eyes.
In fact, G type yellow dwarfs stars ike our Sun make up only 4% of the total stellar population – and our Sun is a relatively hot and massive example of the class G2 being only a couple of steps (G0 & G1) below being a F-type Procyonese star. Spectral class A & F Sirian and Procyonese dwarfs make up 1% with all other higher mass and luminosity classes (W**, O, B plus the chemical classes R, N, S) comprising less than 1% of all stars.
That btw, is excluding the brown dwarfs (spectral classes L &T) completely.
Source : “The Galactic Pyramid” diagram page 31, in “Does Alpha Centauri Have Intelligent Life” by Ken Croswell in ‘Astronomy’ magazine, April 1991.
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* Quixotically enough, the more massive a white dwarf is the smaller -but denser – it gets. So a Neptune mass white dwarf is a lot less massive than a sub-Earth mass example.
** W or WR – Wolf Rayet stars whci are supergiants that have stripped down to their inner layers due to severe cases of stellar wind.
November 3rd, 2011 at 9:05 pm
Good video here.
It looks like the solar disk (white circle) is a lot smaller than the occulting mask.
Wondering what the reasoning for that is & if they’d be able to learn more if the mask was smaller so it more precisely matched the size of the solar disk?
November 4th, 2011 at 3:59 am
The BA said:
Hey, does this mean that the astronauts on the ISS are gonna come home with superpowers?
November 4th, 2011 at 4:05 am
MTU (6) said:
Erm . . . did you instead mean “a Neptune-sized white dwarf is less massive than an Earth-sized white dwarf”?
Neptune’s mass is roughly 17 times Earth’s mass (about 10^26 kg versus 5.9 x 10^24 kg).
November 4th, 2011 at 4:06 am
MTU (7) said:
Diffraction.
November 4th, 2011 at 6:45 am
Can you see some stars moving in the video?
November 4th, 2011 at 7:48 am
Impressive!
Gary 7
November 5th, 2011 at 3:35 am
@11. Kim asked : “Can you see some stars moving in the video?”
Yep, sure can – although I think the star that’s moving is actually the Daytime Star, our Sun. That’s why the background stars appear to shift as STEREO A is keeping the Sun centred.
@ 10. Nigel Depledge : Ah, okay. thanks.
@9. Nigel Depledge : Erm . . . did you instead mean “a Neptune-sized white dwarf is less massive than an Earth-sized white dwarf”?
D’oh! Exactly. I did indeed. Oops. (Facepalms self & blushes.)
November 5th, 2011 at 3:55 am
For a size comparison of lower mass versus higher mass white dwarfs see :
http://scienceblogs.com/startswithabang/2011/09/what_makes_a_supernova_so_supe.php
which forms part of a great well illustrated explanationof supernovae. (Hope its okay netiquette~wise to link this here, BA. Apologies and please let me know if not.)
There’s also a good comparison of white dwarf size-mass varieties here :
http://xoomer.virgilio.it/erectus2/strobel/lives/evolutnb.htm
too.
Whilst this :
http://www.youtube.com/watch?v=po_oUbqa-I8
youtube clip on white dwarfs could be of interest too.
December 6th, 2011 at 11:02 pm
[...] a few of these I had never heard of. Phil Plait describes the importance of understanding the Sun better than I [...]
January 23rd, 2012 at 10:17 am
Based on the vague quantities given, I approximate the energy involved at 100 quadrillion kW-hr. (“a billion tons of matter was hurled away from the Sun at several million kilometers per hour” –> 10^12 kg at n*10^9 m/hr –> 10^12 kg at ~10^6 m/s –> .5*10^24 J –> 1.4*10^17 kW-hr)