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  #1 (permalink)  
Old 15-April-2002, 09:36 PM
John Kierein John Kierein is offline
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Coronal mass ejection. 50-50 chance it's heading our way!
http://www.spaceweather.com/
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Old 15-April-2002, 11:48 PM
Silas Silas is offline
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Might be the first time I've ever agreed with you (friendly grin, and the hoist of a drink of your choice.)

Myself, I'm a modern Antaeus; my feet shall never leave the nurturing soil of the earth (modulo occasional business flights...)

I have the greatest admiration for the real astronauts, as I also do for deep-sea divers, and fire-fighters, and air-sea rescue personnel, and mountain-rescue personnel, and.... Even our own mother earth has no few environments that are wholly hostile to us, and yet we, as an adventurous species, will go there anyway.

From Jason to Magellan to Armstrong, the best and bravest have gone out into the heaving main to bring back knowledge. I couldn't survive ten minutes in their world, and that's only a small part of why they are my heroes.

Silas
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Old 16-April-2002, 12:07 AM
Space Bandito Space Bandito is offline
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I’m the opposite of Silas.

I would gladly go up there (or anywhere) for adventure. Giant Planet Devouring Space Goats be dammed!
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Old 16-April-2002, 12:28 AM
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To my mind, the biggest drawback to being an astronaut would be the journalists who compose dorky headlines like, "Astronauts test drive first railroad in space", hyuk hyuk hyuk.

:: rolleyes ::

Can't get NO respect.

Compared to media headline writers, a super-duper solar flare would be a Sunday School picnic, I'm thinking. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]
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Old 16-April-2002, 02:43 AM
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Quote:
On 2002-04-15 20:07, Space Bandito wrote:
I’m the opposite of Silas.

I would gladly go up there (or anywhere) for adventure. Giant Planet Devouring Space Goats be dammed!
The world needs both you guys - The "Silases" to dream up the missions and get the science done -- and the "Space Banditos" to go there, and lead the way! (Occasionally in history you'll find someone who was also a combination of both.) [img]/phpBB/images/smiles/icon_wink.gif[/img]

But - I do have some serious "Bad Astronomy" questions pertaining to solar flares, coronal mass ejections, and Astronauts in space. (Sorry, I know this was covered before, somewhere.)

How hazardous is this really? If they're in orbit, and a mass ejection is headed their way, what can they do? Is there a real threat to their lives, or not? If there is a threat, does NASA have contingency plans? (Some Russian Cosmonauts have been on very long orbital missions during periods of strong solar activity -- I think they survived.) I've heard that pilots who regularly fly at high altitude get the equivalent of an extra chest x-ray a year. Is that incorrect? (Maybe more "x rays", but not detrimental to health?)

Chip

<font size=-1>[ This Message was edited by: Chip on 2002-04-16 00:33 ]</font>
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Old 16-April-2002, 07:47 AM
4-Lom 4-Lom is offline
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Is a CME a Coronal Mass Ejection (as in some mass is ejected) or is it a Coronal Mass-Ejection? (as in there is a huge amount of 'stuff' ejected)
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Old 16-April-2002, 12:29 PM
John Kierein John Kierein is offline
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It's unhyphenated and the update says it's definitely headed for us and will cause aurora April 17th! The same link works for the update: http://www.spaceweather.com/
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Old 16-April-2002, 12:34 PM
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April 17th? Great, now I know what day we're having a thunderstorm...


-Adam
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Old 16-April-2002, 01:29 PM
John Kierein John Kierein is offline
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These people don't worry about an X-class solar flare or a CME.
http://story.news.yahoo.com/news?tmp...atoday/4029890
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Old 16-April-2002, 03:51 PM
SiriMurthy SiriMurthy is offline
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Quote:
On 2002-04-16 08:29, John Kierein wrote:
It's unhyphenated and the update says it's definitely headed for us and will cause aurora April 17th! The same link works for the update: http://www.spaceweather.com/
I have some questions:
1. what is the streak we see in the lower right of the animated SOHO image?

2. There is a bright point of light in the lower left moving in (relatively speaking) NW direction. Is that a planet?

3. Because of the CME, is Sun losing mass? If yes, by how much per year?
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Old 16-April-2002, 04:01 PM
John Kierein John Kierein is offline
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I'm not sure what the streak is, but it seems to be in just one frame. It may possibly be some contamination from the spacecraft (thruster firing?)? It seems to be moving too fast to be stuff coming directly from the sun??
The bright light is the comet discussed on the website and the other posting. It'll get closest to the sun tomorrow (4/17)
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Old 16-April-2002, 04:20 PM
John Kierein John Kierein is offline
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Oh. This says the streak could well be a cosmic ray. But it's interesting that it points ALMOST directly in line with the sun!
http://www.abc.net.au/science/k2/moments/s218061.htm

<font size=-1>[ This Message was edited by: John Kierein on 2002-04-16 12:26 ]</font>
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Old 16-April-2002, 04:37 PM
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Quote:
On 2002-04-16 11:51, SiriMurthy wrote:
3. Because of the CME, is Sun losing mass? If yes, by how much per year?
Yes, but it's losing even more from the fusion process that's generating the light it's emanating, at least according to this utterly trustworthy astronomer.
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Old 16-April-2002, 04:41 PM
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Quote:
On 2002-04-16 11:51, SiriMurthy wrote:

I have some questions:
1. what is the streak we see in the lower right of the animated SOHO image?
The streak could easily be from radiation, as this image indicates.

(from http://galvin.sr.unh.edu/SOHO/SWT98/index.html )

[Image was bigger than I thought, so I changed it to a link]

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<font size=-1>[ This Message was edited by: ToSeek on 2002-04-16 12:43 ]</font>
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Old 16-April-2002, 04:45 PM
SiriMurthy SiriMurthy is offline
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Quote:
On 2002-04-16 12:37, ToSeek wrote:

Yes, but it's losing even more from the fusion process that's generating the light it's emanating, at least according to this utterly trustworthy astronomer.
So, is CME the same as solar wind?
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Old 16-April-2002, 04:48 PM
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Quote:
On 2002-04-16 11:51, SiriMurthy wrote:

2. There is a bright point of light in the lower left moving in (relatively speaking) NW direction. Is that a planet?
Planets are usually marked with a horizontal line, as in this example. Maybe you've discovered a comet! (Though according to this page, it's not going in the right direction for that. So I'm not sure.
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Old 16-April-2002, 04:56 PM
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[quote]
On 2002-04-16 12:45, SiriMurthy wrote:
Quote:

So, is CME the same as solar wind?
I think it's fair to say that the material in a CME becomes part of the solar wind. Meanwhile, I'm trying to get a number on how massive a CME really is. So far I've gotten three contradictory figures for the high end:

10^11 kg - http://www.owlnet.rice.edu/~bfite/Spac_project.htm
10^13 kg - http://www.windows.ucar.edu/tour/lin....html&edu=high
10^14-10^17 kg - http://edmall.gsfc.nasa.gov/inv99Pro....abstract.html

These are big numbers, but then CMEs don't happen that often.
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Old 16-April-2002, 05:11 PM
John Kierein John Kierein is offline
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The streak is apparently a "solar energetic particle" that is associated with solar flares and CMEs. Much more energetic that the solar wind, so it is travelling faster than the CME. The CME won't get here until tomorrow, but the SEPs may be hitting the astronauts who are doing EVA now - unless the Earth's magnetic field deflects them.

<font size=-1>[ This Message was edited by: John Kierein on 2002-04-16 13:16 ]</font>

<font size=-1>[ This Message was edited by: John Kierein on 2002-04-16 13:17 ]</font>
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Old 16-April-2002, 05:28 PM
SiriMurthy SiriMurthy is offline
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[quote]
On 2002-04-16 12:56, ToSeek wrote:
Quote:
On 2002-04-16 12:45, SiriMurthy wrote:
Quote:

So, is CME the same as solar wind?
I think it's fair to say that the material in a CME becomes part of the solar wind. Meanwhile, I'm trying to get a number on how massive a CME really is. So far I've gotten three contradictory figures for the high end:

10^11 kg - http://www.owlnet.rice.edu/~bfite/Spac_project.htm
10^13 kg - http://www.windows.ucar.edu/tour/lin....html&edu=high
10^14-10^17 kg - http://edmall.gsfc.nasa.gov/inv99Pro....abstract.html

These are big numbers, but then CMEs don't happen that often.
I don't understand. According to our BA's page on Mass Loss the Sun has a total mass of 2 x 10<sup>30</sup> Kilograms. The links above say that the CME is (perhaps) in the order of 10<sup>11</sup> to 10<sup>17</sup> Kilograms???!! [img]/phpBB/images/smiles/icon_confused.gif[/img]

(I have just taken the minimum and the maximum values from the above links.)
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Old 16-April-2002, 05:32 PM
SiriMurthy SiriMurthy is offline
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Quote:
On 2002-04-16 12:48, ToSeek wrote:
Quote:
On 2002-04-16 11:51, SiriMurthy wrote:

2. There is a bright point of light in the lower left moving in (relatively speaking) NW direction. Is that a planet?
Planets are usually marked with a horizontal line, as in this example. Maybe you've discovered a comet! (Though according to this page, it's not going in the right direction for that. So I'm not sure.
I see. So, generally, the comets go towards the Sun, and it makes sense.

So in this page, am I right in understanding that each single line is a comet? If I am, then what does the "bunch" of black lines represent?
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Old 16-April-2002, 06:21 PM
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Quote:
On 2002-04-16 13:32, SiriMurthy wrote:
I see. So, generally, the comets go towards the Sun, and it makes sense.

So in this page, am I right in understanding that each single line is a comet? If I am, then what does the "bunch" of black lines represent?
Each black line represents a comet, specifically a Kreutz sungrazer. The other colored lines are different sorts of comets (except the blue ones, which are still Kreutzes except SOHO was tilted in an unusual way).
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Old 16-April-2002, 09:50 PM