Heliopolis

Palomar · 2004-03-30 21:27:02

Technically speaking, you could have an orbit that actually skimmed the surface of the Sun. As long as you just keep moving fast enough, your orbit will be stable. There's a planned solar probe next decade that will actually do an orbital flyby of the sun, dipping to within <3 solar radii! (<2,000,000 km or 1/75 of an AU or 1/30th the average distance of Mercury to the Sun)...

*How exciting (for a variety of reasons, of course). That pending probe should settle the "are there Vulcanoids or aren't there" question once and for all. It'd be marvelous if there are "Vulcanoids" (more theories, more speculation about our Solar System!).

Amazing that something could dip so closely to the Sun without getting grabbed and gobbled up, even if it is moving swiftly enough.

--Cindy

SBird · 2004-03-31 03:40:10

It does seem amazing but just remember how orbits work. As long as you are going around a gravity source like a planet or star fast enough, you won't fall in. The only thing limiting the closeness of your approach is hitting enough material (atmosphere/gas) to slow you down or cause you to burn up. That and hitting the ground.

About the only thing the solar probe has to worry about is accidentally getting fried by a big prominence or CME that jumps out while it is flying past. That or a Vulcanoid grabbing it. :;):

SBird · 2004-03-31 03:44:15

BTW, here's a [http://solarprobe.gsfc.nasa.gov/]link to the solar probe page.

Also, [http://spacescience.nasa.gov/missions/index.htm]this is a link to NASA's space missions page. It used to be accessible from the NASA front page but they seem to have dropped it in favor of dumb stuff like World's Fastest and Slowest train and other fluff.

Anyway, it's a compendium of all of NASA's past, operating, pending and planned missions.

Palomar · 2004-03-31 14:39:42

BTW, here's a [http://solarprobe.gsfc.nasa.gov/]link to the solar probe page.
Also, [http://spacescience.nasa.gov/missions/index.htm]this is a link to NASA's space missions page. It used to be accessible from the NASA front page but they seem to have dropped it in favor of dumb stuff like World's Fastest and Slowest train and other fluff.
Anyway, it's a compendium of all of NASA's past, operating, pending and planned missions.

*Thanks for the links, SBird. I've begun reading at both sites. It seems they've given the probe a rather lackluster name.

I wish they would give the Solar Probe a bit more attention at space.com, spaceweather.com, etc. (even if it is slated for the upcoming decade).

I'm especially grateful that they included the "Near-Sun Trajectory" graph at the "Spacecraft" page.

--Cindy

Palomar · 2004-04-01 08:54:05

[http://www.solarviews.com/cap/index/sun1.html]Solar Moss (and other images)

*There's a very nice image site [http://www.solarviews.com/cap/index/sun1.html]here. I've been studying/following solar astronomy for a while now, but I don't recall reading/hearing about the "solar moss" phenomenon before. The _Cambridge Encyclopedia of the Sun_ (I have a copy) is rather sizeable, but I don't recall seeing a reference to it in there (yet). Hmmmm, I wonder what other surprises are in store. I do so much reading and etc.; perhaps it's slipped my mind. :-\

[http://www.solarviews.com/cap/sun/moss2.htm]Explanation of "solar moss"

There are 78 images for viewing at the first link. The feathery-appearing "solar structure details" and fire loops are especially intriguing. I've seen video clips of fire loop movement, etc.

--Cindy

::EDIT:: The resource also includes links to other astronomy items of interest (discuss elsewhere please; I'd like to keep this thread focused on the Sun...thanks).

SBird · 2004-04-01 12:40:03

It seems they've given the probe a rather lackluster name.

Heh, I'm hoping that Solar Probe (is it just me or does anyone else get a mental image of one of those old generic 'beer' cans when they hear that name?) is just a working name for now. I vote for Dante for the actual name. :;):

Palomar · 2004-04-01 12:51:26

It seems they've given the probe a rather lackluster name.
Heh, I'm hoping that Solar Probe (is it just me or does anyone else get a mental image of one of those old generic 'beer' cans when they hear that name?) is just a working name for now. I vote for Dante for the actual name. :;):

*I think they should paint orange and yellow flames all around the cone of it (ala custom car design) and name it the Helioscreamer.

That's what came to my mind, anyway, when I first looked at the web site.

It deserves a better name than merely "Solar Probe," considering the uniqueness of the mission and all.

--Cindy

SBird · 2004-04-01 13:32:24

Ah, and then when they do wakeup calls to it 'ala the Mars rovers, you can send rockabilly tunes to it.

Palomar · 2004-04-03 07:51:12

[http://www.spacedaily.com/news/genesis-04a.html]Genesis coming home

*Another mission nearly completed. Re-entry (of sample return capsule) is scheduled for September 8. Lots to look forward to; I love it!

"Genesis is NASA's first sample return mission since the last Apollo mission in 1972, and the first ever to return material collected beyond the Moon. The science collection began November 30, 2001..."

--Cindy

::EDIT:: Dramatic in-air helicopter recovery:

"On May 2, 2004, the spacecraft will fly past Earth, positioning itself for daylight recovery. Four months later, the sample-return capsule will make a dramatic Earth entrance by parachuting toward the ground at the Utah Testing and Training Range of the U.S. Air Force.

--->Specially trained helicopter pilots will catch the capsule in midair<--- to prevent the delicate samples from being disturbed by the impact of a landing.

*Wish I could be there to watch.

SBird · 2004-04-03 19:52:12

Incidentally, Genesis is the mission using the 0-energy trajectories we've been discussing over in the 'Interplanetary Propulsion' section.

Palomar · 2004-04-06 15:15:04

[http://www.space.com/scienceastronomy/m … 40406.html]Click

*A rather ambitious study. How many "laps" around the Galactic Center do you think Sol has completed since its "birth"?

Also includes a really funky animation which shows the Sun's 250-million-year (to complete just -one-) orbit around the GC. ("A lot has changed. The stars begin the animation spread broadly across about a quarter of the galaxy, then gather to a small, seemingly insignificant huddle at the end."). I noticed in the animation, around the 7 or 8 o'clock position, a certain "twist" effect. Not quite sure what to call it.

Says older stars "in particular" move more rapidly than previously known.

"Tracing the movements back in time with a computer, the researchers found that most of the stars were once much farther from the Sun than they are today."

Also says that, contrary to the expectation the Milky Way has become "rather calm" since its early history, "this turns out not to be true. Stars have been perturbed all the time throughout the Milky Way history."

Well, here's some cool history about Sol and its place in the Milky Way, where it's been and what's near us now, etc.

--Cindy

Palomar · 2004-04-13 14:12:30

*This just in from space.com's Astronotes:

---
~China Plans to Launch Space Solar Telescope~

According to a report on the Xinhua news agency website, Chinese scientists plan to launch China’s first space solar telescope into orbit sometime between 2006 and 2010.

According to Ai Guoxiang, head of the National Astronomical Observatory and a member of Chinese Academy of Science, the telescope would be attached to a space satellite and launched into orbit about 467 miles (750 km) above Earth.

Orbiting high above the atmosphere, the telescope would be free from atmosphere disturbances and operate around the clock sending data back to Earth, Guoxiang told the Shenzhen Daily.
---

*Do you suppose China will share whatever information it gleans from this?

--Cindy

Palomar · 2004-04-19 08:07:45

[http://www.spaceweather.com/swpod2004/1 … almer1.jpg]Restless Sol

*Spaceweather.com is advising Sol enthusiasts with filtered 'scopes to keep a check on the solar limb, as this week is ripe with "glowing magnetic loops big enough to swallow dozens of planets..."

The pic above was taken by Mr. Gary Palmer of California. He used a narrow bandwith red Hydrogen-alpha filter. Oooooo, I envy him!

I'll have my solar screen keeping tabs of sunspot #596.

--Cindy

Palomar · 2004-04-30 05:59:37

*A burning ring of fire (lovely!):

[Pic by Mr. Andrew Chatman]

---

*The Phoenix rises!

[Pic by Mr. Charles Tilley]

---

*To large to copy as "Image" here. The guy (Mr. Gary Palmer) who took this pic is -always- taking great pics of the sun! Oooooo, I am envious.

http://science.nasa.gov/spaceweather/sw … g]Terrific granulation detail & huge magnetic filaments

--Cindy

Palomar · 2004-05-07 09:58:55

*Dang...just about the time I think I've pretty much gone over Astropix archives, another gem pops up.

http://antwrp.gsfc.nasa.gov/apod/ap000524.html]This is from SOHO. Check out the *huge* coronal mass ejection...and the Pleiades and four planets -- all in this one image.

Excellent.

--Cindy

Palomar · 2004-05-08 11:00:16

http://www.spacedaily.com/news/genesis-04a.html]Genesis coming home
*Another mission nearly completed. Re-entry (of sample return capsule) is scheduled for September 8. Lots to look forward to; I love it!
"Genesis is NASA's first sample return mission since the last Apollo mission in 1972, and the first ever to return material collected beyond the Moon. The science collection began November 30, 2001..."
--Cindy
::EDIT:: Dramatic in-air helicopter recovery:
"On May 2, 2004, the spacecraft will fly past Earth, positioning itself for daylight recovery. Four months later, the sample-return capsule will make a dramatic Earth entrance by parachuting toward the ground at the Utah Testing and Training Range of the U.S. Air Force.
--->Specially trained helicopter pilots will catch the capsule in midair<--- to prevent the delicate samples from being disturbed by the impact of a landing.
*Wish I could be there to watch.

http://www.spaceref.com/news/viewpr.htm … 77]Genesis on final lap to home

*Mentions helicopter retrieval again [September 8], in the article...hopefully they'll make a good, clean catch :-\ "To preserve the delicate particles of the Sun, specially trained helicopter pilots will snag the return capsule from mid-air using custom-designed hooks. The flight crews for the two helicopters assigned for Genesis capture and return are comprised of former military aviators and Hollywood stunt pilots." Now that's something I'd like to see.

---
"'Saturday, we brushed past Earth just beyond the Moon's orbit. On September 6, we will again approach Earth at lunar distance, but this time we are going to come on in carrying NASA's first samples from space since Apollo 17 carried the last moon rocks back in December of 1972.'

The Earth flyby occurred at about 3:00 a.m. Pacific Daylight Time on Saturday, May 1, at an altitude of 386,000 kilometers (239,850 miles) above the planet's surface - just beyond the Moon's orbit. At that time, the spacecraft was traveling at a speed relative to Earth of 1.26 kilometers per second (2,800 miles per hour)."
---

*I was reading my _Cambridge Encyclopedia of the Sun_ the other day. I'll put this in my own words [except for 3 direct quotes in " "]. It mentions the "wonderful balancing act" in the Sun, i.e. it's controlled by its "temperature-sensitive nuclear reactions" which act like a thermostat. When the Sun's gravity pulls it in and makes it a bit smaller, it becomes hotter and its nuclear fusion proceeds at a quicker rate. This causes particles to move faster, creating more pressure, and so pushes the Sun back out. The Sun then cools a bit as it expands outward, restoring it to its original temperature. [Of course if the Sun expands a bit too much it cools down a little inside, the nuclear reactions slow down, and its gravity pulls the Sun inward again, restoring equilibrium. Reminds me of inhalation and exhalation. ] "So the pendulum keeps swinging between gravity and fusion, with no winner. That is how the Sun harnesses its nuclear energy, and it has been doing that for 4.6 billion years."

How fabulous.

I suppose this isn't "news" to some folks here, but you know me...

--Cindy

::EDIT:: http://www.jpl.nasa.gov/genesis/mission … Apparently the Genesis folks have been practicing retrieval. Great pics.

Palomar · 2004-05-11 06:19:12

*Sunspot #606. Over Greece (Mr. Wooseas took the pic):

*Sunspots have 11-year activity cycle. I'm a bit surprised a sunspot of that size (typical for this year anyway, in size) is so high up on the solar globe (generally spots this size are nearer the solar equator). Have seen pics and illustrations from previous years of very huge spots -and- in small clusters.

Sunspots also affect our weather; I need to read up more on theories as to how, etc.

Last year scientists predicted Sol would be settling down, but I'm hoping for larger sunspots and in clusters soon.

--Cindy

::EDIT:: I just recalled that the 11-year cycle is divided; 5-1/2 years of maximum activity and likewise for minimum.

Palomar · 2004-05-14 07:21:36

*Sunspots have 11-year activity cycle. I'm a bit surprised a sunspot of that size (typical for this year anyway, in size) is so high up on the solar globe (generally spots this size are nearer the solar equator). Have seen pics and illustrations from previous years of very huge spots -and- in small clusters.
Sunspots also affect our weather; I need to read up more on theories as to how, etc.
Last year scientists predicted Sol would be settling down, but I'm hoping for larger sunspots and in clusters soon.
--Cindy
::EDIT:: I just recalled that the 11-year cycle is divided; 5-1/2 years of maximum activity and likewise for minimum.

http://antwrp.gsfc.nasa.gov/apod/ap010411.html]Now *that's* what I call sunspots

http://science.nasa.gov/spaceweather/im … g.gif]Nice animation of current sunspot activity...a bit wimpy, though

*C'mon Sol...how about a repeat from that 2001 pic? You can do better than the current mamby-pamby sunspots you're producing. :down:

--Cindy :laugh:

Palomar · 2004-05-15 22:29:16

*Hmmmm...here's some cool stuff I read in my _Cambridge Encyclopedia of the Sun_. Won't quote of course; will relate the info in my own words.

The existence of the 11-year (roughly...sometimes is 10 years, sometimes 12) sunspot cycle was first suggested by a guy named Samuel Heinrich Schwabe, in the early 1840s. He was a pharmacist and amateur astronomer from Dessau, Germany. He observed the Sun for over 40 years, taking meticulous notes (and drawings/sketchings) I presume, etc. He noticed the roughly decade-long variation in total numbers of sunspots. The book doesn't say -how- he made his observations (I presume observing them in foggy or heavy-mist conditions during sunrise/sunset).

Anyway, another guy named Rudolf Wolf from Zurich, Switzerland (and professional astronomer) introduced a relative sunspot number which could be compared for all observers, in 1848. He also initiated an international collaboration which confirmed sunspot cycles. He did some historical research as well, and the book's author says Wolf's evidence indicated the 11-year sunspot cycle has been constant since the year 1700.

During maximums in the cycle it's usual to find 100 or more spots on Sol at any given time. At minimum of course few are seen, and Sol can go for a month without any spots. The maximum sunspot number has fluctuated by a factor of as much as 2 over the past century (20th). Another interesting bit of history: Apparently sunspots practically disappeared altogether from Sol for a 70-year interval ending in 1715. Hmmmmm.

More later.

--Cindy

Trebuchet · 2004-05-16 01:44:48

Well, from what I remember, the Jesuit who discovered sunspots back in the time of Galileo projected them onto a screen. Presumably that method was what the guy in the 1840's used, because even through fog and heavy mist will fry your eyes through a telescope.

Nice pictures, though, keep 'em rolling.

Palomar · 2004-05-16 07:30:18

because even through fog and heavy mist will fry your eyes through a telescope.

*Yes indeed.

The people I referred to from yesteryear, observing sunspots through mists and fogs, observed the spots with the unaided eye. There's at least one reference (perhaps a couple) earlier in this thread as to the method they used; unaided eye observing the Sun (especially during rise or set) through fog, etc.

My husband and I observed (unaided eye) a huge sunspot last November during a thick sand and dust storm in our area.

Of course, otherwise you must use projection (I have a solar screen attachment for my telescope) or a filter (either one of those super-expensive jobs which attach to an eyepiece, or the specially-coated "lens-cap" type [less expensive]).

--Cindy

::EDIT:: http://www.spaceweather.com/images2004/ … if]Sunspot 609 continues to grow: May 12 - 16 animation

*From SOHO, posted at spaceweather.com

Trebuchet · 2004-05-16 11:38:29

If he was tracking large numbers of sunspots, he was using a projection screen. Eyes can see sunspots, but you miss the smaller ones that way.

Palomar · 2004-05-16 11:59:01

If he was tracking large numbers of sunspots, he was using a projection screen. Eyes can see sunspots, but you miss the smaller ones that way.

*Not necessarily. My 'scope and projection screen don't show the smaller sunspots, even at higher magnifications. I check the number of 'spots I can see with my screen against the daily number of 'spots at spaceweather.com and my screen displays substantially less 'spots than the daily number reported by the pros.

Besides, the articles don't imply the observers from yesteryear saw every spot; they simply recorded what they did see. And yes, some of them doubtless used projection.
Not all the articles I've read about sunspot observers of yesteryear say -how- the spots were observed (the articles should, however, try to pinpoint the method used by those observers). A few of the articles do say "unaided eye" and make no mention of projection; simply looking through a thick fog, etc.

Of course, Sol appears bloated upon sunrise and sunset, which may have assisted in viewing smaller spots (which would also appear larger at the time, due to the atmospheric distortion).

--Cindy

Palomar · 2004-05-19 05:36:52

*Recent HUGE solar prominences:

http://www.spaceweather.com/swpod2004/1 … .jpg]Click

Images too large to post as "Image" (I tried that...)

Those pics courtesy Mr. Gary Palmer of California, posted by spaceweather.com. Wow.

"In a few days, several sunspots are due to glide over the sun's western limb. The sunspots themselves will vanish, but their towering magnetic fields won't. Giant magnetic loops filled with glowing-hot gas will jut into the black of space above the limb, producing what astronomers call prominences."

The sunspot number is also fluctuating rather wildly lately...54 then jumps to 141 then back down to 91 today.

I took my 'scope and solar screen out day before last...very nice "peppering" of Sol's disc.

--Cindy

Palomar · 2004-06-01 16:53:28

http://www.space.com/php/multimedia/ima … en.]Golden ribbons of the Sun

*Closest, most detailed image of Sol yet.

Photo credit is due to Sweden's 1-meter Solar Telescope on the island of La Palma, Spain.

Flux tubes proven:

"Surprisingly, new small-scale magnetic field structures were revealed, explained Tom Berger, a solar physicist at the Lockheed Martin Solar and Astrophysics Lab in Palo Alto, California. The smallest 'elements' of the Sun’s magnetic field can be observed as they arrange themselves in the turbulent flowfields of the Sun’s surface.

A variety of magnetic formations that had not previously been detected on the Sun were seen in the images, Berger said.

--->For the first time, after 30 years of hypothesizing and solar observing, small discrete blobs of magnetic fields – dubbed 'flux tubes' – were viewed."<---

--Cindy

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