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Space Mailbag: What's Up with the Sun?
Space.com ^ | November 5, 2003 | By Robert Roy Britt

Posted on 11/06/2003 12:23:19 AM PST by Aracelis

Questions about the Recent Wild Solar Activity

Readers had many questions about the recent, historical round of 10 solar flares in two weeks and their associated space storms (called coronal mass ejections, or CMEs) that hit Earth. I got behind with the Mailbag because the flares just would not stop -- blame it on the Sun! -- but here, finally, are some answers (recent additions at the top):

Kurtis writes: Is there a possibility that since humans have really only existed for .01% of our Sun's total lifetime, that the Sun is in the process of returning to its norm, and everything we have seen so far in the history of our star has been atypical and the recent activity is just the Sun resuming its normal pattern?

RRB: Hmm. I might buy some of that. You're right that scientists don't know enough about the Sun to predict all the nuances of its cycles and extremes.

We have good records of solar activity for just four centuries (starting with Galileo's observations of sunspots -- see below) and scant written records going back a few more centuries. Tree rings and ice core samples give strong clues about what the Sun was doing hundreds and even many thousands of years ago. But we don't know much about what it really used to do. The Sun is about 4.6 billion years old.

However, studies of other stars like our Sun -- younger and older -- provide indirect evidence for the Sun's past and likely future, so scientists are not totally, ahem, in the dark.

Now, all that said, a study earlier this year suggested -- this is not proven -- suggested that solar activity has been increasing for the past century, perhaps longer. Keep in mind, though, this old weather forecaster's axiom: A single bad storm, or even several in a row, does not signal a shift in long-term climate patterns.

Lynn writes: The way the Sun has been acting is kind of scary. Just what the heck is going on for so many out-of-season eruptions? Are the scientist beginning to wonder if something big is headed our way ... something never before seen from our Sun?

RRB: The series of powerful flares is indeed unusual. But there is no cause for serious concern beyond the effects possible from the individual storms (to satellites, communication and power grids). Humans on the ground are not in danger.

Like any star, the Sun is volatile. Imagine a campfire: It might burn calmly for a long stretch and then suddenly whip into a temporary frenzy. You might be surprised, but you'd think of it as relatively normal. That said, solar physicists will no doubt look into this amazing series of storms in hopes of learning more about what's behind them. The Sun remains largely mysterious.

By "out-of-season," you mean that the 11-year solar cycle peaked about two or three years ago and activity is generally in decline. That's true. Interestingly, though, historical data show that more major flares occur at this stage of the cycle than during the period of maximum solar activity. Just one more mystery.

Earnie writes: How fast does the Sun rotate on its axis? Is it likely that the current sunspots will still be active on the next rotation or next several rotations of the Sun? How long do sunspots last on average?

RRB: The Sun spins once on its axis every 25 days at its equator. It takes about 35 days for the ball of gas to rotate near its poles. Sunspots sometimes form and fizzle in a matter of days. Other times they last weeks.

Any of the three large sunspots seen over the past two weeks could rotate back into view in about two weeks.

Here's a cool fact: Galileo Galilei, back in 1612, discovered the Sun's rotation by noting the movement of sunspots. When he died in 1642, he was blind. Some accounts blame his blindness on an infection, but most experts agree looking at the Sun had something to do with it. Never look at the Sun!

Ann writes: Any chance these solar flares can interrupt airline travel or flight capabilities?

RRB: That possibility exists. The flare on Tuesday, Oct. 4 disrupted radio communications -- causing a total blackout at some wavelengths -- and increased radiation at high latitudes, such as the polar routes taken in trans-Atlantic flights. Last week, communications with pilots were disrupted. And some airlines rerouted planes for more southerly passages, based on a first-ever alert issued by the FAA.

There is little agreement on whether a typical passenger is at any great risk, however. NOAA estimates an airline passenger can experience as much radiation as 10 chest X-rays during a geomagnetic storm. This figure is debated. Experts do agree that anyone on a high-altitude jet, or an astronaut in space, is exposed to more radiation than someone on the ground. More here.

Laura writes: With all the recent activity the Sun has been sending our direction what could we expect if our protective geomagnetic field begins to weaken, or worse, what if our magnetic poles were to reverse as they have done many times in the past history of the Earth?

RRB: The magnetic field can get temporarily tired, one expert told me, so that back-to-back storms -- separated by hours -- might be more effective in penetrating Earth's natural defenses. This situation was set up last week, but we survived. Storms separated by days are not thought to gain any easier entry, however, at least not according to present knowledge. I'm not aware of any studies suggesting short-term solar activity can have anything to do with reversing Earth's magnetic field.

Jason writes: Is the space station shielded heavily enough for such activity from the Sun. That kind of exposure of radiation for such a long time cannot be good for anyone.

RRB: You're right that extra doses of radiation pose health risks. NASA monitors what astronauts are exposed to and limits their time in space. During intense storms, the residents of the International Space Station retreat to the Russian Zvezda service module -- the most protective. They did so several times last week. More about what the crew did last week is here. And here is a story about the radiation risk in general. Also, here's some interesting news about the radiation risk at Mars.

George writes: Is the Sun possibly preparing to enter the red giant phase of life? Are these flares a sign of the end for us?

RRB: No. The Sun is middle-aged at 4.6 billion years. It won't start swelling into its red giant phase for a few billion years. When that happens, anyone remaining on Earth will indeed be in trouble.

Mike writes: What is the likelihood of the CME affecting the asteroid belt? Does the CME have enough force to alter any of the asteroids?

RRB: I'm not aware of any studies done to quantify this. The orbits of asteroids are altered by sunlight. It's called the Yarkovsky effect and, over time, a rock's orbit and rotation change ever-so-slightly due to the constant radiation pressure. A flare would presumably add to that effect, but it's such a minor thing in the grand scheme that it would not have any near-term consequences, like redirecting a space rock immediately to Earth.

Scientists have pondered using the Yarkovsky effect to deflect an asteroid, if one were ever determined to be on a collision course decades or centuries down the road. Simply paint it white, perhaps, and let the Sun gently nudge it off course over the years.

Declan writes: Last week there was an article about an unexplained shadow (or storm), below and to the right of Jupiter’s Great Spot. Then this week, another highly unusual (nay unique) event takes place with the appearance of two huge sunspots and associated storms, in a period when the Sun is supposed to be winding down to minimum activity. … Has anybody investigated the possibility that the two events may be in some way connected?

RRB: The spot on Jupiter was probably a locally generated atmospheric phenomenon, according to astronomers who regularly watch the gas giant planet. There's no reason I know of to think such spots -- similar ones have been seen before -- would have anything directly to do with increased solar activity, though solar energy in general certainly affects Jupiter. In this case, the Jovian spot came and went before the Sun got active, however.


TOPICS: Miscellaneous; News/Current Events
KEYWORDS: solarflares; sun

1 posted on 11/06/2003 12:23:20 AM PST by Aracelis
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To: RadioAstronomer; VadeRetro; whattajoke; js1138; CobaltBlue; Barnacle; Doctor Stochastic; ...
Ping!
2 posted on 11/06/2003 12:24:07 AM PST by Aracelis
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To: Piltdown_Woman

3 posted on 11/06/2003 12:45:26 AM PST by South40
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To: South40
Great image! Do you have a date for this event?
4 posted on 11/06/2003 12:48:52 AM PST by Aracelis
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To: All
The Sun has a Thousand Faces--- Thread 3
5 posted on 11/06/2003 12:51:33 AM PST by backhoe (Just an old Keyboard Cowboy, ridin' the trakball into the Sunset...)
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To: Piltdown_Woman
No date. But here's another...


6 posted on 11/06/2003 12:56:04 AM PST by South40
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To: South40
Magnificent...I was searching for good images earlier this evening. One of my co-workers (who admittedly has lead a cloistered life) asked me to explain solar flares. I found a few images, but now I can show her these. Thanks!
7 posted on 11/06/2003 12:59:23 AM PST by Aracelis
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To: Piltdown_Woman; billbears; 4ConservativeJustices; stainlessbanner
Luke 21:25,26:

25. And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring;

26. Men's hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken.

8 posted on 11/06/2003 3:34:41 AM PST by Ff--150 (Now unto Him Who is able to do)
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To: Piltdown_Woman
It's global warming I tell ya, we have made the Earth so over-warm that it is starting massive fires on the Sun.
9 posted on 11/06/2003 4:28:43 AM PST by trebb
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To: Ff--150
The Sun is about 4.6 billion years old.

Given its current mass and the rate of decay/loss of matter, if it were this old the sun would have been much more massive, and burnt the earth to a crisp or its gravity would have sucked the earth into its maw.

10 posted on 11/06/2003 5:07:23 AM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: Piltdown_Woman
Thanks for the heads up!
11 posted on 11/06/2003 5:21:44 AM PST by Alamo-Girl
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To: 4ConservativeJustices
You know something physicists don't know?
12 posted on 11/06/2003 6:10:24 AM PST by js1138
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To: 4ConservativeJustices
Given its current mass and the rate of decay/loss of matter, if it were this old the sun would have been much more massive, and burnt the earth to a crisp or its gravity would have sucked the earth into its maw.

Great point, thanx.

13 posted on 11/06/2003 7:20:42 AM PST by Ff--150 (Now unto Him Who is able to do)
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To: 4ConservativeJustices
Please show your caculations for this.
14 posted on 11/06/2003 7:39:08 AM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: 4ConservativeJustices
Maw-sucking decay-lossing earth-crisping sun, anyways.

I hate the sun.

15 posted on 11/06/2003 7:45:43 AM PST by Lazamataz (PROUDLY SCARING FELLOW FREEPERS SINCE 1999 !!!!)
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To: Piltdown_Woman
Laura writes: With all the recent activity the Sun has been sending our direction what could we expect if our protective geomagnetic field begins to weaken, or worse, what if our magnetic poles were to reverse as they have done many times in the past history of the Earth?

That looks like a question a geologist would ask. I was thinking of it myself... Is that you?

Bill
16 posted on 11/06/2003 7:50:13 AM PST by Barnacle (A Human Shield against the onslaught of Leftist tripe.)
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To: js1138
You know something physicists don't know?

God.

17 posted on 11/06/2003 8:43:10 AM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: Doctor Stochastic
4.6e9 years x 4.2e9 kg/s mass lost = 6.1e26 kg loss and a change of 4.6e4 kilometers in mean distance. That's assuming that all mass is lost through nuclear fusion, that our ability to calculate the loss per second is accurate and that the rate has remained constant. There's no way to prove that it has or hasn't. I simply find it hard to believe that the Sun will be burnt out with 99.93% of its mass remaining. Just as I find it impossible to believe that mass simply "popped" into existance from nothingness.
18 posted on 11/06/2003 9:05:50 AM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: 4ConservativeJustices
if it were this old

Been studying Chandrasekar's work?

19 posted on 11/06/2003 9:12:31 AM PST by RightWhale (Close your tag lines)
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To: RightWhale
Been studying Chandrasekar's work?

Nah, I read a lot of different stuff, throw out hyperbole, and sometimes just take things the wrong way ;o)

20 posted on 11/06/2003 9:19:40 AM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: Ff--150
Those verses have crossed my mind of late. Thank you!
21 posted on 11/06/2003 9:24:50 AM PST by Aracelis
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To: 4ConservativeJustices
Those things you find "hard to believe" and that are generally accepted may require some study to see why. Stellar evolution is rather well understood.

The total relative mass loss by the Sun from all reasons in only 9.13*10**(-14) per year.
22 posted on 11/06/2003 9:26:48 AM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Barnacle
That looks like a question a geologist would ask. I was thinking of it myself... Is that you?

Not this time, although the question has been on my mind.

23 posted on 11/06/2003 9:37:22 AM PST by Aracelis
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To: 4ConservativeJustices
4.6e9 years x 4.2e9 kg/s mass lost = 6.1e26 kg loss

Very good. And how massive do you think the sun is?

I simply find it hard to believe that the Sun will be burnt out with 99.93% of its mass remaining.

Why? How much would you expect to remain?

24 posted on 11/06/2003 9:48:50 AM PST by Physicist
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To: Piltdown_Woman
here's a thought, catalyzed in part by a comment back up the thread:

Has anyone investigated solar flare/CME activity coincident with reversal of the Earth's magnetic field as a mechanism for Mass Extinction in Earth's history?

If you were to have heavy solar activity during a period when the Earth's magnetic filed were changing polarity, I'd think there'd be a period of vulnerabilty during which the earth's surface would be bathed in x-rays from the flares and CME's.

Would there be an detectable remnant of such X-ray activity in the gelogic column, such that we could correlate such an event chronologically and compare it to instances of Mass Extinctions?

Or, be I all wet?

25 posted on 11/06/2003 9:51:52 AM PST by longshadow
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To: Piltdown_Woman
26. Men's hearts failing them for fear, and for looking after those things which are coming on the earth:

Today doctors assert one out of two Americans will have heart problems? Perhaps we do suspect changes on the way? :-)

26 posted on 11/06/2003 10:25:33 AM PST by Ff--150 (Now unto Him Who is able to do)
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To: longshadow; RadioAstronomer
I smell another research project. :^)

Off-the-cuff I'd say we may be able to correlate terrestrial fission tracks and the relative abundance of noble gases with paleomagnetic data, similar to work done on chondrites. Here are some interesting links:

Two-Stage Model of Protoplanetary Irradiation

Excess cosmogenic noble gases relative to chondritic matrix

Solar Gases in the Earth by Solar Wind Irradiation?

27 posted on 11/06/2003 10:47:15 AM PST by Aracelis
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To: Piltdown_Woman
"The sun, the Sun? Well it's kinda like this my little darlings........

......It just keeps building pressure, building pressure, building pressure and building some more and more and more pressure till one day it just POPS like a big, fat pimple! It's really disgusting......."


28 posted on 11/06/2003 10:53:00 AM PST by myheroesareDeadandRegistered
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To: Ff--150
I agree that massive changes are on the way. Simple reflection on the differences between American society from the time I was born and today, reveals much. I suspect today's fast-paced lifestyle has stripped from us our illusion of civility, and we are left with the most basic of human rights having to be publicly litigated and legislated.
29 posted on 11/06/2003 10:55:54 AM PST by Aracelis
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To: Doctor Stochastic
The total relative mass loss by the Sun from all reasons in only 9.13*10**(-14) per year.

If the Sun is to have 99.93% of it's original mass (hydrogen to helium) left after 10 billion years, wouldn't the rate per year be 7e-12?

30 posted on 11/06/2003 12:02:09 PM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: Physicist
And how massive do you think the sun is?

1.99e30 kg.

How much would you expect to remain?

A lot less. Why do stars collapse? A .03% change in mass shouldn't cause it should it?

31 posted on 11/06/2003 12:22:33 PM PST by 4CJ (Come along chihuahua, I want to hear you say yo quiero taco bell. - Nolu Chan, 28 Jul 2003)
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To: 4ConservativeJustices
It isn't just the change in mass. As the hydrogen burns to helium, the star no longer produces enought energy to counteract its self-gravitation. Check with an astrophysics book or one of the better encyclopaedias (Britannica is good.)
32 posted on 11/06/2003 12:41:43 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: 4ConservativeJustices
1.99e30 kg.

Very good. Now do you see why your reply #10 was wrong?

A lot less. Why do stars collapse? A .03% change in mass shouldn't cause it should it?

Why does a hot air balloon collapse, when you turn the burner off?

33 posted on 11/06/2003 1:13:03 PM PST by Physicist
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To: 4ConservativeJustices
Why do stars collapse?

It's all about pressure balance. Pressure outwards is from radiative pressure, photons actually pushing on the matter, pressing inward is our old friend gravity. In nearly all stars, the pressure balance is enough to prevent collapse.

Most stars never collapse, the only ones that do are stars that go supernovae. As was said earlier, that only happens if the the star doesn't output enough energy to counteract the inward pressure of gravity. This occurs when the star runs into a fusion process that doesn't create energy, but actually takes energy to react. That process is the process of fusing two iron atoms together, and it only occurs at temperatures of several hundred million degrees celsius. This only happens in very high mass stars, like most O type stars.

34 posted on 11/06/2003 1:27:06 PM PST by ThinkPlease (Fortune Favors the Bold!)
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To: Piltdown_Woman; John H K; RightWhale; SamAdams76; Diddle E. Squat; petuniasevan; Truth666; ...
IMPACT: A coronal mass ejection hurled into space by the superflare described below swept past Earth today (Nov. 6th) at approximately 1930 UT. Mild-to-moderate geomagnetic storms and high-latitude auroras are possible during the hours ahead.

http://www.spaceweather.com/

35 posted on 11/06/2003 4:00:58 PM PST by Barnacle (Navigating the treacherous waters of a liberal culture)
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To: Piltdown_Woman; Barnacle
Thanks for the post PW and thanks for the ping Barnacle. Looks like the Sun is sleeping it off.....http://www.sec.noaa.gov/rt_plots/xray_5m.html
36 posted on 11/06/2003 4:59:53 PM PST by Davea
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.
37 posted on 11/06/2003 9:29:43 PM PST by StriperSniper (All this, of course, is simply pious fudge. - H. L. Mencken)
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