Explanation: Captured in colorful telescopic portraits, two cosmic owls glare back toward planet Earth in this intriguing comparison of planetary nebulae. On the left is M97 in the constellation Ursa Major, also known in the northern hemisphere as the Owl Nebula. On the right is its visual counterpart, the southern Owl Nebula in the constellation Hydra, cataloged as PLN 283+25.1. Both nebulae are remarkably symmetric, round, and similar in size, some 2 light-years across or about 2,000 times the diameter of Neptune's orbit. Planetary nebulae are produced during a final phase in the life of a sun-like star, an example of the fate that awaits the Sun when it runs out of nuclear fuel in another 5 billion years. Both images were made using narrowband filters and different color mappings. The image of the southern Owl also includes broadband data, bringing out the surrounding star field.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 4:09 am
by Astronut
AHHHH - this is more like it! No ionized this or Quantum that - just a couple of good looking marbles to stare at all day. Gee, i hope God dose not lose ALL His marbles, someone has to run things.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 4:17 am
by neufer
-------------------------------------
____ Hamlet, Prince of Denmark Act 4, Scene 5
OPHELIA: They say the owl was a baker's daughter
-------------------------------------
____ A Midsummer Night's Dream Act 2, Scene 2
TITANIA: Some war with rere-mice for their leathern wings,
___ To make my small elves coats, and some keep back
___ The clamorous owl that nightly hoots and wonders
___ At our quaint spirits.
-------------------------------------
____ Titus Andronicus Act 2, Scene 3
TAMORA: These two have 'ticed me hither to this place:
___ A barren detested vale, you see it is;
___ The trees, though summer, yet forlorn and lean,
___ O'ercome with moss and baleful mistletoe:
___ Here never shines the sun; here nothing breeds,
___ Unless the nightly owl or fatal raven:
-------------------------------------
____ Venus and Adonis Stanza 87
'Look, the world's comforter, with weary gait,
His day's hot task hath ended in the west;
The owl, night's herald, shrieks, ''Tis very late;'
The sheep are gone to fold, birds to their nest,
And coal-black clouds that shadow heaven's light
Do summon us to part and bid good night.
-------------------------------------
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 5:14 am
by owlice
Owls!!
: swoons :
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 8:07 am
by tesla
If the Sun runs on so called nuclear fuel, why then has the Chromosphere a temperature in the millions of degrees yet the surface is only the thousands? Nuclear THEORY dictates the surface should be hotter than the Chromosphere as you are moving further away from the heat source. Why is it when you look at closeup photos of sunspots, the inside of the sun is black? Or the twisted filaments?
Observed measurements of the Sun is the same as having an open fire in your house but the hottest temperatures is outside!
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 12:04 pm
by Astronut
WHO - WHO - i say, has interjected the Sun's functioning into the OWL's discussion?
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 12:09 pm
by biddie67
owlice wrote:Owls!!
: swoons :
Couldn't help laughing at this .... I'm fascinated by the owls in my area but I'm also leery of the great horned owls here.
Just last Sunday evening, a great horned owl made a run after my half-grown kittens playing in the driveway just at dusk. If my dog hadn't been on the alert and interrupted the owl's run, I would have been missing one of my cats.
Seeing one of those big winged birds swooping down from its hidden perch in a tree is awesome ....
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 12:23 pm
by biddie67
from the APOD description: ....the fate that awaits the Sun when it runs out of nuclear fuel in another 5 billion years ....
How is it known that the sun's fuel will run out in 5 billion years?
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 1:10 pm
by neufer
biddie67 wrote:
How is it known that the sun's fuel will run out in 5 billion years?
http://en.wikipedia.org/wiki/Sun wrote:
<<The Sun was formed about 4.57 billion years ago when a hydrogen molecular cloud collapsed. Solar formation is dated in two ways: the Sun's current main sequence age, determined using computer models of stellar evolution and nucleocosmochronology, is thought to be about 4.57 billion years. This is in close accord with the radiometric date of the oldest Solar System material, at 4.567 billion years ago.
The Sun is about halfway through its main-sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than four million metric tons of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation. At this rate, the Sun has so far converted around 100 Earth-masses of matter into energy. The Sun will spend a total of approximately 10 billion years as a main sequence star.
The Sun does not have enough mass to explode as a supernova. Instead, in about 5 billion years, it will enter a red giant phase, its outer layers expanding as the hydrogen fuel in the core is consumed and the core contracts and heats up. Helium fusion will begin when the core temperature reaches around 100 million kelvins and will produce carbon, entering the asymptotic giant branch phase.
Earth's fate is precarious. As a red giant, the Sun will have a maximum radius beyond the Earth's current orbit, 1 AU, 250 times the present radius of the Sun.However, by the time it is an asymptotic giant branch star, the Sun will have lost roughly 30% of its present mass due to a stellar wind, so the orbits of the planets will move outward. If it were only for this, Earth would probably be spared, but new research suggests that Earth will be swallowed by the Sun owing to tidal interactions. Even if Earth would escape incineration in the Sun, still all its water will be boiled away and most of its atmosphere would escape into space. Even during its current life in the main sequence, the Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising. The Sun used to be fainter in the past, which is possibly the reason life on Earth has only existed for about 1 billion years on land. The increase in solar temperatures is such that already in about a billion years, the surface of the Earth will become too hot for liquid water to exist, ending all terrestrial life.
Following the red giant phase, intense thermal pulsations will cause the Sun to throw off its outer layers, forming a planetary nebula. The only object that will remain after the outer layers are ejected is the extremely hot stellar core, which will slowly cool and fade as a white dwarf over many billions of years. This stellar evolution scenario is typical of low- to medium-mass stars.>>
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 1:30 pm
by owlice
biddie67 wrote:Couldn't help laughing at this .... I'm fascinated by the owls in my area but I'm also leery of the great horned owls here.
Just last Sunday evening, a great horned owl made a run after my half-grown kittens playing in the driveway just at dusk. If my dog hadn't been on the alert and interrupted the owl's run, I would have been missing one of my cats.
Seeing one of those big winged birds swooping down from its hidden perch in a tree is awesome ....
You have, or at least your cats have, good reason to be leery! Yikes!
Over on the biking forum I sometimes post on, the subject of night rides came up, and another local rider wrote that she has seen owls on her night rides. For me, that's a good reason to ride at night (even though most of what I see are bugs headed for my face; what incentive to stop mouth-breathing when biking)!
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 1:37 pm
by Hofi
The similarity of this nebulae is really astonishing!
While looking at them, a question penetrated into my mind: Why and How is it that the colors at the edge of the nebulae are stronger than in the inner side? Is it because of the higher density of material/gas?
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 2:00 pm
by Chris Peterson
Hofi wrote:While looking at them, a question penetrated into my mind: Why and How is it that the colors at the edge of the nebulae are stronger than in the inner side? Is it because of the higher density of material/gas?
This is common with planetary nebulas. There are two things going on: the objects are usually shell-like, so the outer edge is often higher density, and they are usually spherical or tubular, so from our viewpoint we are looking through more material at the edge. Both of these effects combine to make the edges look brighter than the interior.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 2:20 pm
by Hofi
Chris Peterson wrote:from our viewpoint we are looking through more material at the edge
Thanks for the information!
... but why is it that the density at the outer edge are denser? Shouldn't it be that the density decreases to the outside?
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 2:31 pm
by Chris Peterson
Hofi wrote:... but why is it that the density at the outer edge are denser? Shouldn't it be that the density decreases to the outside?
Because the planetary nebula is the product of a sort of explosion which throws off a shell of material. In the extreme case, there may be nothing in the interior at all, and all we are seeing is a shell. So the "interior" from our viewpoint is just the front and rear wall of a spherical shell, while the "edges" are deep views through the top, bottom, left, and right walls of that shell.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 2:56 pm
by Astronut
The story of the Owl and the pussycats(kittens) by biddie67 reminded me of something even scarier that happened to me about a half century ago.
When i was somewhere around 10-12 yrs old, my mother tried to teach me how to cup my hands together and blow through my thumbs to make a noise.
Well, no matter how i tried i just could not do it.
one night when i was outside in front of the house with a fire going in the fire pit, i was trying to make the sound with my hands cupped together. I got so frustrated that i thought i would give it some help so I made a sound into my cupped hands.
I thought to myself - HEY, that sounds like the owl off in the distance. So i started doing it as close to how the owl sounded as i could and i must have done pretty well as after a few minutes the owl was NOT off in the distance anymore!
In fact it was so close that i could hear the small sound they make after a regular hoot. It sounds almost like the purr of a cat but is only about 1-2 seconds long.
I stopped my 'hooting' and after what seemed like forever - about 30 seconds - this really BIG shape silently glided about 6 feet over my right shoulder, by the fire and out into the darkness.
It almost scared the dung right out of me!
I went into the house and stayed there.
I soon found out that the sound i could make was so owl like that crows would come in to try and drive the owl away.
That was good back then because I and my cousin were both avid crow and woodchuck shooters.
One day when he was visting i told him about what happened that first night. Needless to say he did not belive it, so we went out back in the woods and i showed him.
When a whole bunch of crows came swooping in looking for the owl in the tops of the trees, my cousin was going nuts with excitment.
The only bummer was that we could see the shadows of the constantly moving crows just above the tree tops, but we could not really tell where they were so we could not shoot them.
My cousin tried to learn how to 'hoot' but never could get the hang of it.
So now, if anyone says that i don't give a 'Hoot' about anything - i can prove them wrong.
Re: APOD: Northern and Southern Owls (2010 May 06)
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 7:30 pm
by emanna
Greetings,
Looking at the picture today I could not help but be amazed and how similar this looks to fluorescently labeled cells that I work with. Given the huge order of magnitude in size difference it is really incredible. I have attached a link to a couple of a cells so you can see for yourself.
Red is epithelial/cytoplasmic antibody stain
Blue is nuclear stain
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 8:04 pm
by wonderboy
emanna wrote:Greetings,
Looking at the picture today I could not help but be amazed and how similar this looks to fluorescently labeled cells that I work with. Given the huge order of magnitude in size difference it is really incredible. I have attached a link to a couple of a cells so you can see for yourself.
Red is epithelial/cytoplasmic antibody stain
Blue is nuclear stain
Ur right, it kinda does, but i shouldnt need to sign up to a new site to see ur pics. Bystander might do u for spamming.
either way, it made me look sumthin up n taught me something new.
Thank you
Paul.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 8:07 pm
by biddie67
Thanks neufer .....
It seems that we (i.e., this human species) needs to get cracking if we are going to accomplish an entire species migration to another safe stellar/planet environment before the Sun gives out - we haven't even been able to set up a permanent colony on the Moon yet ...
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 8:10 pm
by biddie67
emanna wrote:Greetings,
Looking at the picture today I could not help but be amazed and how similar this looks to fluorescently labeled cells that I work with. Given the huge order of magnitude in size difference it is really incredible. I have attached a link to a couple of a cells so you can see for yourself.
Red is epithelial/cytoplasmic antibody stain
Blue is nuclear stain
emanna: I just tried to look at the pictures also and stopped at the signin/signup - could you copy your pictures into this BB?
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Thu May 06, 2010 9:04 pm
by wonderboy
biddie67 wrote:Thanks neufer .....
It seems that we (i.e., this human species) needs to get cracking if we are going to accomplish an entire species migration to another safe stellar/planet environment before the Sun gives out - we haven't even been able to set up a permanent colony on the Moon yet ...
Well the more I think about it, I think the reason we havent met aliens is because they havent advanced themselves enough to escape the impending doom of their parent star or stars. This might be true of all civilizations. We might leave our planet to go to mars, but what then? titan or something?
Its scary to think that one day, and one day soon in space time this planet is not going to be here. if we havent killed ourselves by then, that will.
Paul.
We need to get CRACKING!
Posted: Fri May 07, 2010 2:07 am
by neufer
biddie67 wrote:It seems that we (i.e., this human species) need to get cracking if we are going to accomplish an entire species migration to another safe stellar/planet environment before the Sun gives out - we haven't even been able to set up a permanent colony on the Moon yet ...
Click to play embedded YouTube video.
Re: APOD: Northern and Southern Owls (2010 May 06)
Posted: Fri May 07, 2010 2:13 pm
by biddie67
Astronut wrote:The story of the Owl and the pussycats(kittens) by biddie67 reminded me of something even scarier that happened to me about a half century ago.
When i was somewhere around 10-12 yrs ..........
Great story! And it gave me a great tip on how to hoot back at the owls around here. I have tried hooting back at the Great Horned Owls when I hear them around here but they recognize my "alien accent" and just shut up and wait for me to go away.
The cupped hands give an extra timbre to my hoot (as I tried it sitting here at the computer) that seems to better match the calls of the owls - tonight, if I hear them, I'm going to try it on them.
With a chuckle and a thanks, I'll be ready to duck .....