Since we’ve been talking about snow quite a bit recently, this seems fitting. WUWT reader Tom in Texas tips us to this image:
A composite of archival Hubble data taken with the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys. Like a whirl of shiny flakes sparkling in a snow globe, Hubble caught this glimpse of stars in the globular cluster M13. The cluster is home to over 100,000 stars, packed closely together in a ball approximately 150 light-years across, and is located at a distance of 25,000 light-years. Picture: AFP / NASA / ESA
Click here to see a high-res version of the Hubble snow globe I wonder what the sky would look like from a world in the center of that cluster? Would some of the stars look like bright marbles in the sky?
If you really want to see some interesting things from the HST, have a look at this gallery:
Hubble Space Telescope Advent Calendar 2009
Like the photo above, it gives some perspective about our place and scale in the universe.
Oh! That is so wonderful!
You can shake this snow globe, too – by clicking on the high-res link and then quickly minimizing it and maximizing it repeatedly. ( the little + and – lens)
A beautiful picture — thank you, sir. If our little solar system were in there, it wouldn’t even be noticeable at fifty times the resolution.
Wonders and wonderings and wonderments abound…
“I wonder what the sky would look like from a world in the center of that cluster? ”
I wonder that of myself when I use my telescope. Just imagine if any civilisation evolve one of the planets there, they could colonise a big part of the cluster.
The distances are much less between star-systems and planets.
This could make a Hollywood sci-fi. The thousands of planets, with many different aliens, empires and rebels.
And off course planets could wonder about systems.
Oh, I can smell the popcorn already…
Wow… Stars close enough to each other that interstellar travel might actually be possible.
So, is this a circular picture because the HST cuts off into a circular image, or is the shape actually that round? Looks artificially round to me, but space has strange things in it…
I wonder what the sky would look like from a world in the center of that cluster?
Dazzling for an instant, then black.
Given the concentration of white and blue stars, you’d probably fry from the UV radiation. Pretty from down here, though.
O.K., if the solar system is currently hurtling through a 6000 C gas cloud, how does that affect optical accuracy?
Since we’ve got an astronomical topic I thought I’d repost this suggestion I made a little while ago from astronomy but which I think the climatologists might find worth considering. Sorry for the length but it’s easer for everyone rather than reading all the articles.
During MIT’s “The Great ClimateGate Debate” (http://mitworld.mit.edu/video/730) Lindzen said he was very surprised (although pleased) about the recent interest in climate science by the general public, and even named Watt himself and his temprature station project.
I think that with projects like Watt’s ground station survey, McIntyre and McKitrick’s double checking of fishy peer reviewed work, Willis, RomanM and others double checking the raw temperature data, I think it is clear that amateur climate science has reached a new maturity that calls for a formal pro-am collaboration forum — a “Pro-Am Climate Science Institute”.
For those who think this is a radical idea it is not new and below are examples from two sciences where I know there is extensive and valuable pro-am collaboration. It is an obvious solution for those sciences that study parts of the natural world where the sheer volume and/or vast geographic distribution is just too great for professionals to do alone. Climate science is an area where this is the case. The opportunities from just the above projects have enough work to keep an army of volunteer amateurs involved indefinitely, along with new projects (like perhaps establishing a network of amateur temperature instruments).
Having a formal pro-am collaboration forum will also help neutralize critics that ignore people like the Watt himself by giving volunteers credibility as they contributing as equals. Jones wanted to “redefine what peer-reviwed literature was” (e-mail 1089318616.txt) so perhaps we can do it for him (he seems a bit busy right now) A pro-am forum also helps legitimate scientists in the field (ie the non-warmists) to tap into an army of helpers when needed. And probably it will bring many other benefits. No doubt the idea will be scoffed at by the warmists but I think those who are already doing this level of pro-am work should consider forging forward with this as over time it will be accepted.
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Amateur astronomers have many, many formal pro-am collaboration relationships and organizations that are valued and embrased by professionals. Amateurs have even detected planets oribiting other stars, a feat that has only just becaome possible for professionals a decade or so ago. Here’s are a few examples of the sophisticated level of collaboration taking place, although in the early years it was tough going as pros were reluctant partners, but now about 5 years later its 180 degree turnaround.
Pro-Am collaboration to unveil the atmosphere of Venus
http://www.europlanet-eu.org/demo/index.php?option=com_content&task=view&id=46&Itemid=41
Results from an ongoing collaboration between amateur astronomers and the European Space Agency to support the Venus Express mission will be presented at the European Planetary Science Congress in Potsdam on Wednesday 22nd August. Silvia Kowollik, from the Zollern-Alb Observatory in Germany and one of the participants in the project, said, “This is the first time there’s been a European collaboration between amateur astronomers and scientists. In the United States, they have a long tradition and a lot of experience in this kind of work. In Europe we are just starting.” “There have been huge advances in relatively cheaply available equipment, which means that amateurs can take images in wavelengths from infrared through to ultraviolet with impressive accuracy and content. These amateur observations are the last link in a chain that starts with Venus Express and continues with the professional ground-based activities. When joined together, all these observations will all help to peel back the atmosphere of Venus and reveal her mysteries.”
Amateur Discovers Gamma-Ray Burst Afterglow
http://www.skyandtelescope.com/news/3307961.html?page=1&c=y
Last July 25th Berto Monard of Pretoria, South Africa, became the first amateur astronomer to discover a gamma-ray burst’s fading visual afterglow. Dubbed GRB 030725, the burst was first spotted by the NASA/Massachusetts Institute of Technology High Energy Transient Explorer-2 (HETE-2) spacecraft, which immediately relayed its approximate coordinates to astronomers worldwide.
Gamma-Ray Bursts monitored by Amateurs
http://www.pbs.org/seeinginthedark/astronomy-topics/gamma-ray-bursts.html
The afterglow starts to fade right away, so the earlier you catch the explosion, the more likely you are to be able to photograph the afterglow. Astronomers have sent x-ray telescopes into orbit to scan the sky, to catch the first x-ray afterglow of a burst as soon as possible. The latest of these satellites, called Swift, has been making a slew of discoveries since its launch in November 2004. True to its name, the Swift satellite instantly dispatches e-mail alerts to amateur and professional astronomers around the world. Many observers alerted by Swift will be on the wrong side of the world or under cloudy skies, but a few have a chance to catch the visible afterglow. As there are many more amateur than professional astronomers, and many have the kinds of telescopes and CCD cameras needed to measure the fading brilliance of a gamma-ray burst, the odds are that the discovery will be made by an amateur. As described in our film, the amateur astronomer Michael Koppelman captured just such an image, and it turned out to be one of the most distant gamma-ray bursts ever observed—its distance a staggering 11 billion light years. One day when the different kinds of gamma-ray bursts are better understood, it is likely that the amateur astronomy community will have played a significant part in exposing the secrets of these violent events.
Astronomers Launch Pro-Am “Registry” (check out the amateur’s observatory)
http://www.skyandtelescope.com/news/3309186.html?page=1&c=y
The past decade has seen an explosion in the number of backyard observers using high-end equipment and sophisticated software to record faint asteroids, discover supernovae, and even detect extrasolar planets. So it’s not surprising that many accomplished amateurs yearn to contribute directly to scientific research. Among the dozens of practicing astronomers attending the AAS special session was Alan Harris (Space Science Institute), who points out that amateur observers have determined about a third of the 1,500 known rotation periods for asteroids. “Amateurs are always thanking us for the interest we professionals show in their work, but I think it’s going in the wrong direction,” Harris comments. “It’s we who should be thanking them for their involvement.”
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Another example is in ornithology
Association of Field Ornithologists
http://www.afonet.org/about/index.html
The Association of Field Ornithologists (AFO) is a membership organization dedicated to the study and conservation of birds and their natural habitats. The AFO prides itself as serving as a bridge between the professional and the amateur ornithologist. The organization’s membership and governing council consist of both amateur and professional ornithologists, in recognition of the contributions that both make to ornithology.
hmmm, guess its possible but seems amazing. 4/3 * pi * 75^3 = 1.8 million cubic light years divided by 100000 = average distance between stars 17.7 light years. Obiously there are alot of them way closer to each other than that.
Spectacular photo, the link to the calendar was amazing.
Is the black surround a ‘picture frame’ or is the cluster that (presumably) spherical shape?
This is a lovely picture and thank you for posting it. Re life in a star cluster – looks beautiful to us, but has anyone read Nightfall by Isaac Asimov?
Still, as EM Smith has said, interstellar travel would be somewhat easier in such a crowded place. What we’re looking at here could be something similar to the Romulan Empire – perhaps a good thing for us that it’s 25,000 light years away!
Sometimes, when I wake up in the morning and meditate about the universe, I can’t help thinking to myself,
“Man, this is the shit! Who ordered all this?”
One can only imagine that many of those stars are orbited by planets similar to those in our solar system. Unfortunately, imagination is all we’ve got at this time. It’s wonderful just the same.
Thanks for the awsome picture. It made my day.
Christopher Hanley (23:02:38) :
> Is the black surround a ‘picture frame’ or is the cluster that (presumably)
> spherical shape?
It’s a sphere. Here’s an excellent amateur image (wider field of view)
http://stoney-hills.com/html/m13.html
E.M.Smith (22:45:04) :
Wow… Stars close enough to each other that interstellar travel might actually be possible.
How much closer would you like to be to our sun? It’s pretty, but can in support life?
Actually… that’s 1 star per 17.7 *cubic* light years, making it some 3.2ly on average between stars, assuming an even distribution. Of course, the distribution is not even, but denser towards the middle of the cluster.
Final post 🙂
Here are some excellent deep sky images by amateur astronomers:
http://www.yankee.us.com/images2.html
http://www.feraphotography.com/Gallery.html
http://www.imagingdeepsky.com/
http://www.galaxyphoto.com/
Can you tell I’m an amateur! Enjoy what “amateurs” accomplish!!
Happy New Year and best wishes.
The Archive at
has some stunning vistas.
http://antwrp.gsfc.nasa.gov/apod/archivepix.html
Andrew Parker (22:51:53) :
O.K., if the solar system is currently hurtling through a 6000 C gas cloud, how does that affect optical accuracy?
Not at all. The solar wind filling the solar system has a ‘temperature’ of some 20,000C [right this minute] and we see the planets quite well.
Leif Svalgaard (23:33:00) :
Not at all. The solar wind filling the solar system has a ‘temperature’ of some 20,000C [right this minute] and we see the planets quite well.
I apparently don’t have the knowledge you have Leif, but I can’t help but question your claim. Does that include our solar system? And if so or if not, at what speed is it traveling? And is it losing temperature as it travels? And if so, at what rate?…just asking.
Do I see double Sun’s? These are Suns that rotate around each other.
Or are those galaxies rotating around each other?
Ah yes…
The Hercules globular cluster. I’ve looked at it with my telescope at home… a glorious beauty that literally brought tears to my eyes the first time I viewed it under perfect dark sky conditions.
M13 was the very first deep sky object I found when I first started into astronomy as a hobby. With an 8″ telescope I could literally see thousands of tiny points of light.
Puts a smile on my face as I’m typing this.
Ah, the wonders of the universe… something that’s definately not anthropogenic.
The strange thing is my intersest in WUWT’s traditional subjects and one theory that links planetary movements to different cycles of solar activity has drawn me into rediscovering gravity.
As the AGW debate has grown old and the warmist’s get shrill in intellectual defeat as they rightly trumpet political success … I find myself hunting down books discussing Einstein’s equations and what is next. Modified Gravity theories that do away with dark matter are especially interesting.
I highly recommend this video of Newton’s equations being derived from Einstein’s equations.
gtrip (23:57:08) :
but I can’t help but question your claim. Does that include our solar system? And if so or if not, at what speed is it traveling? And is it losing temperature as it travels? And if so, at what rate?…just asking.
On what ground would you question this?
Our solar system is filled with a hot gas [called the solar wind] with a temperature varying between 10,000C and 100,000C or more. Right now the temperature is 27,100 C. The Earth is travelling through this gas at a speed of 30 km/sec. The solar wind is expanding and the temperature is slowly decreasing, but remains hot throughout.
gtrip (23:57:08) :
Leif Svalgaard (23:33:00) :
Not at all. The solar wind filling the solar system has a ‘temperature’ of some 20,000C [right this minute] and we see the planets quite well.
I apparently don’t have the knowledge you have Leif, but I can’t help but question your claim. Does that include our solar system? And if so or if not, at what speed is it traveling? And is it losing temperature as it travels? And if so, at what rate?…just asking
Not sure which claim you’re questioning? The fact that there is a solar wind or the fact that it’s at approx 20,000 degrees?
You have to remember that the density of the material in question is of fundamental importance – you can have a medium that is extremely “hot” (say millions of degrees) but if it is suitably “thin” or sparse then you could easily put your hand in it without ill effect. When dealing with interstellar material the densities are often very low (relative to what we’re used to on earth they can essentially approach a vacuum).
From what I remember (would have to dig out the old text books or even Google it…) the solar wind(s) travel at anywhere between 400-800km/s – and I assume it loses “temperature” as it travels. (I presume the loss rate is a balance between the radiation from the particle as a black-body to space against any solar radiation incident on the particle, the latter obviously diminishing as the particles get farther from the sun – this assumes that conduction effects are minimal in the medium).
Of course I could be wrong about all of the above – it’s been a while…
Cheers
Mark
For an extraordinary photo of the Tarantula Nebula
http://www.eso.org/public/images/eso0650a/
And wide-field images
http://canopus.physik.uni-potsdam.de/~axm/images.html#wide-field
Have a Happy New Year
Mal
Leif, I think gtrip has confused temperature with heat density. The solar wind is very hot, but it also has a low heat density which is why the Earth doesn’t ‘burn up’ by being inside a 20,000+ C gas. The gas is too tenuous to do that.
len (00:36:34) :
If you’re really interested in proper gravity knowledge, go to http://astrowww.phys.uvic.ca/~tatum/ under celestrial mechanics section. All the equations you need are there. He covers all, integration too, from ground up and is quite thorough. I think you’ll like it for a reference. Its one of mine.
Leif, gtrip and Graeme, you have it all wrong.It is 20,000 million degrees 2 miles down.
Happy New Year everyone.
It is cut off. The HST field of view is very narrow.
M13 is actually quite accessible with an amateur telescope, and just as beautiful. Here is one of my backyard images of it:
http://arnholm.org/astro/deepsky/m13/m13_20060416.jpg
There is lots of stuff out there. If you look in the 11 o’clock position in my image, near the top, you see a spiral galaxy called NGC6207.
The universe is a beautiful place. Reality beats fantasy.
gtrip: as Graeme suggests, one problem you seem to be having in believing Leif’s statement is a confusion between the definitioms of temperature and heat (not heat density per se). There also seems to be some confusion regarding temperature and black bodies. Black bodies are a hypothetical construct which many large, energetic objects (like the Sun) can be reasonably approximated as. Small particles (like those is the solar wind) are almost completely electrons, ionized atoms and very simple molecules, and electronically excited neutral atoms and very simple molecules. These particles by *no means* behave anything like a black body. They radiate and absorb energy not by classical black body laws (at rates proportional to their tenperate to the fourth power) but by quantum mechanical laws which are governed by state densities and electronic selection rules (i.e., they absorb and emit only at very specific and very narrow portions of the spectrum).
This also means that the whole ensenble is almost perfectly transparent at wavelengths where there are no existing transitions or the transitions are disallowed by selection rules. Even where allowed transitions exist, as suggested earlier, the particle density is so low that it would have little impact. So, for instance, the earth’s atmosphere would almost certainly have a larger total absorption at almost any absorption or emission frequency than the solar wind. This is why you have to use a space-based instrument to see it and it’s still hard work doing so.
Hope that helps.
I am sure that with proper adjustments and appropriate value added data, the solar wind is getting warmer.
Wonderful stuff. Yet there are people who claim they can define the creator of all that glory. I wonder if they have ever looked through a telescope or even looked at the Hubble pictures.
Fun to image, but still a bit of a challenge to get that just-right image stretch:
http://www.robertb.darkhorizons.org/m13c.jpg
When NASA annouced they were going to abandon Hubble some years ago, the imagination went wild. What amatuer astronomer wouldn’t want a 96″ RC in his backyard?
Carsten Arnholm, Norway (02:42:09) :
You can see the red stars in M13 through a 25″ Dob (as red stars).
These Hubble photos are the very best of this Internet thingy. The photo series at boston.com are routinely amazing. Thanks for the link.
Pamela Gray (00:13:11) :
Do I see double Sun’s? These are Suns that rotate around each other.
Pamela Gray (00:23:15) :
Or are those galaxies rotating around each other?
What you need to visualise is that all those stars are in space – so they’re not just sitting there. All of them are in orbit within the globular cluster – many of these orbits highly elliptical, around the cluster centre of gravity, so many of the stars zoom in to near the centre of the cluster, then crawl out to its outer edges.
Then this, and other globular clusters, are in orbit in a spherical cloud around our Galaxy. Globular clusters can be seen around other galaxies as well.
Yes, some (many?) of them will be double stars. Also, because of the closeness of the stars in the centre, they interact gravitationally, so existing multiple systems could be separated, and new ones formed. There’s a report on that suggestion here.
(They are stars in the cluster, not galaxies – though there could be some distant background galaxies in the image.)
Great image – though I still don’t think it beats staring up at the real sky in a truly dark location, with no Moon and a bright Milky Way, and visualising the disk of our galaxy, with the Sun and all its planets orbiting through the disk of stars.
Andrew Parker (22:51:53) :
O.K., if the solar system is currently hurtling through a 6000 C gas cloud, how does that affect optical accuracy?
Leif Svalgaard (23:33:00) :
Not at all. The solar wind filling the solar system has a ‘temperature’ of some 20,000C [right this minute] and we see the planets quite well.
gtrip (23:57:08) :
but I can’t help but question your claim. Does that include our solar system? And if so or if not, at what speed is it traveling? And is it losing temperature as it travels? And if so, at what rate?…just asking.
Leif Svalgaard (00:42:06) :
On what ground would you question this?
Our solar system is filled with a hot gas [called the solar wind] with a temperature varying between 10,000C and 100,000C or more. Right now the temperature is 27,100 C. The Earth is travelling through this gas at a speed of 30 km/sec. The solar wind is expanding and the temperature is slowly decreasing, but remains hot throughout.
There is a major difference in the gases in the solar wind than in a (much cooler) interstellar gas cloud. The solar wind is so hot, that all of the gases are completely stripped of their electrons. The solar wind is mostly an equal mix of protons and electrons. Spectrographic analysis of the solar corona performed during a total solar eclipse confirms that the very high temperatures existing in the corona ALTERS the spectra of the gases. To assume that the solar wind and an interstellar gas cloud would have the same optical qualities because they are both comprised of the same gases is a fallacy.
I have worked with helium (He) excited to a plasma state inside an Inert Gas Plasma Generator in a laboratory, and have observed that the helium in plasma form partially occludes visible light. This is with only a 5 inch thickness of plasma inside a clear quartz vacuum chamber evacuated to a pressure of 100 millitorr. The helium plasma I observed would be much closer in temperature to an interstellar gas cloud, than is the solar wind to such a cloud.
“One good lab experiment is worth a thousand expert opinions”
It is great to see you back and blogging again on WUWT Dr. Svalgaard. You have been missed.
I, personally, have been gone for about a month. Moving to Alaska is not an easy feat. And so much has happened during my move. Climategate, Copenhagen, Colder temperatures. It will take me at least a week to catch up on all the posts since Thanksgiving.
But, with all that said, my passion still lies in heliophysics. The foundation to understanding terrestrial climate lies in understanding space weather. We will not be any closer to predicting climate here on earth until we have a better grasp on the study of heliophysics. I believe that.
Try to imagine having a sound card, a video card, a memory chip and processor, but not having a motherboard. Until we solve the basic concepts of space weather, PDOs, El Ninos and any other of earths anomalies will remain a mystery.
This post alone is evidence how little is known about space weather. Or more importantly, sifting through posts to understand real factual science, sidestepping the pseudo-science bloggers that wish to muddy the science of heliophysics, has become quite a feat in and of itself.
So once again, it’s a pleasure to see you back Leif.
Otherwise, I’m afraid people would fall into some trap, thinking that cosmic clouds in the local bubble are hell bent on destroying us.
Had to be said. Sorry.
We gonna need a star tax out there to combat the number of stars. They stars will kill us all! We need to prevent the number of stars in the galaxy from exceeding…
Lets just enjoy a nearer body tonight and enjoy a Blue Moon 🙂
toyotawhizguy (05:17:57) : I tried to find an absolute pressure for the vacuum of space. I would assume it is a lot less than 100 millitorr. I did find that rather than use pressure, it is allegedly too vague at the pressures and temps of space, that they use a count of particles per cm^3. While your temp may be similar, I would assume pressure is higher, therefore density/optical distortion is higher.
What interests me about globular clusters is why they don’t collapse into a single gigantic star/supernova. Are they orbiting a mutual centre of gravity?
“I wonder what the sky would look like from a world in the center of that cluster?”
Isaac Asimov’s best short story,”Nightfall”, was based entirely on that question.
Just a couple of speculative questions for those who understand the universe:
1) What happened before the Big Bang, or was it always a steady state?
2) If the universe is infinite, how can infinity expand on itself?
Take infinity to mean that time and space has no beginning or end, or in the case of time, there is not a moment that did not precede another moment
Robert Wykoff (22:52:48) :
> Obviously there are alot [a lot] of them way closer to each other than that.
Look at a photo of Andromeda or some other spiral galaxy. See all the stars packed into the arms? We’re in something very much like that The stars you see are all close to us in the arm. The rest of the galaxy is the Milky Way and can’t compete with street lights on Earth.
I’ve long wondered what the night sky looks like to an owl. BTW, in unforested areas star light is adequate for walking. I once made it from the Phantom Ranch to the “unapproved” campsite we had on the Colorado River in the Grand Canyon. We couldn’t use lights because the ranger because the ranger might catch us.
On the other hand, I ran out of daylight in the White Mountains in New Hampshire once. The key ring LED flashlight I had saved us from needing a rescue. Incredibly bad planning on my part. (The timing, not the light.)
Mick (22:44:07) :
E.M.Smith (22:45:04) :
A cluster may have it’s advantages, as shorter distances
which would allow interstellar travel or at least some emigration by “slowtrain”, generational, sub-light spaceships.
But it has it’s lacks, too:
Supernovaes may be more often, thus the chance for civilisations
to be wiped out by that is much higher than in our,
much more – rural – part of the galaxy.
More, the heavy elements are not evenly distributed over the galaxy.
There are not everywhere enough to support live and civilisations.
Last: The capability to build generational spaceships depends not
only on technical factors. Economic and sociological factors
may weigh more heavy.
Generally, we have most of the technology to build a
rather primitive spaceship, which may have a speed
of light/0.01.
To survive out there we need at least 20,000 people aboard.
So the spaceship as to have at least a volume of 2 to 3 million
cubic yards.
Now, to build it, my assumption is:
At least 50 years time from start to completion.
Approx. 1 million scientists, engineers and technicians may be
necessary for the whole project.
Approx. 3 to 5 percent of global GNP (gross national product) as costs.
At least 25 years as refresh/recreation time for the global economy
between each build.
For the people remaining on earth,
there will be no return on investment on all that.
So, for how long the populace will support the project?
My personal rule of thumb for it: No civilisation will support
more than three builds, because the people most eager to support
are from the same type as the people who like to be aboard.
(well educated, optimistic, and to them, chance has more meaning than danger. The pool of that type of people is always limited.)
IMHO there is a chance of 1/3trd, that any spaceship will successfully
reach its destination. More, I think it’s only a chance of 1/10th, that
that it’s big crew will successfully survive on a new planet and create a new civilisation.
More, with sub-light spaceships, distances of more than 50 lightyears
have to much constraints. So, even by consecutive successes, you are
always bound to your local part of the galaxy, there is no chance to successfully travel the empty distances between the spiral arms of the galaxy.
Nevertheless, sooner or later we will need to try space travel that way.
Simply, to not to have all eggs in one basket (earth, solar system).
Oh dear, with a 25″ there is not much you can hide! However, as I am using eye-glasses, I tend to use a b/w CCD camera (or webcam) instead of an eye-piece. I am a ‘proud owner’ of a C8 and a 60mm Takahashi apo refractor. The M13 image I linked to was using the Tak, small apertures can also be useful!
And yes, getting the image stretch right is always a balancing act….
The last couple of years have been terrible for amateur astronomers over here. From the outset, at 60N the summer is always too bright and the winter too cloudy. These days (nights!) the skies are full of ice crystals reflecting light & destroying contrast, if we ignore the fact that it is -20C. But the spring and autumn have usually brought some opportunities. However the last few years have brought ‘wall-to-wall’ clouds like I cannot remember seeing before. I secretly call them Svensmark clouds.
“Actually… that’s 1 star per 17.7 *cubic* light years, making it some 3.2ly on average between stars, assuming an even distribution. Of course, the distribution is not even, but denser towards the middle of the cluster.”
Excellent point, Gabriel.
Although I’m not sure how you got that number.
My first idea was that every star was at the center of its own little sphere. Using that assumption, I did the following math:
Find the radius of that little sphere:
r = (3/4 * 1/pi * vol)^1/3
so, in this case,
r = ((3*17.7)/(4*3.14159) )^1/3
r = 1.41 ly
so the distance (on average) between two stars should be
2 * 1.41 ly = 2.82 ly (i.e. from the center of one sphere to the edge, and then from the edge of the opposite sphere it touches to the center of that sphere)
But then I realized this was a problem because there would be a lot of unaccounted for space between the spheres (since they don’t pack into a solid) and therefore the number I got wasn’t really reliable.
So, then I was thinking that I should put each star at the center of a little cube because they would pack into a solid and would approximate the little sphere in concept. The length of one side of that cube would be:
s = 17.7^1/3
s = 5.9 ly
Meaning, on average, the distance to the next closet stars, at least in the six primary directions toward the faces of the cube, would be 5.9ly (half of the starting cube plus half of the destination cube).
But other stars are at different angles so I don’t know how well my approximation holds up.
Is there an accepted formula or concept for making this calculation?
An interesting view on global clusters:
http://www.thunderbolts.info/tpod/2005/arch05/051216m15cluster.htm
Robinson (06:16:39) :
What interests me about globular clusters is why they don’t collapse into a single gigantic star/supernova. Are they orbiting a mutual centre of gravity?
Yes, of course (or perhaps more precise: it is a complex multi-body system). These things are huge and far away so they appear static to us. But in reality they are very dynamic, the laws of gravity are just as valid over there as they are here.
The M13 globular cluster is ~145 light years in diameter and about 25000 light years from us….. the angular diameter as seen from here is ~23 arc minutes, i.e.slightly less than the Sun and the Moon.
Cool !
How big is the Bulk anyway? I’ve seen the Hubble Deep Filed photos of a pin point location of the edge of our known Universe. It was filled with galaxy clusters. I suppose there are galaxies beyond those too.
I have seen a commenter here say gravity and falling are the same—from Einsteins concept—so the commenter said the Universe is falling. He didn’t stop to imagine that out Universe could actually be orbiting something, maybe another Universe in the Bulk, and not falling.
Re:Stellar density….it is almost unbelievable but…if two galaxies with billions of stars….were to collide with each other…they would pass through each other without a single stellar collision !!!
Wow, that’s a lot of bugs in front of the camera lens.
Don’t you hate it when the flash makes them stand out like that?
😉
Globular clusters….down here in the southern Hem we have two spectacular ones, 47-Tuc and ω Centauri ….these clusters are very old and lie outside the plane/disc of the galaxy and are rumoured to be unsuitable for organic life…The globular cluster ω Centauri is the most-studied stellar system of our Galaxy, but nevertheless one of the most puzzling. It hosts different stellar populations….tidal stripping may explain its present size…it has been proposed that it was once a dwarf elliptical galaxy but was then tidally disrupted by the Milky way galaxy…however it is still probably the largest of the globular clusters …
David Allan…”The foundation to understanding terrestrial climate lies in understanding space weather. We will not be any closer to predicting climate here on earth until we have a better grasp on the study of heliophysics. I believe that.”
very well put…I often wondered what the effect on the earth,s climate would be if the sun was just slightly “variable” a sort of minor deltascuti star !!!
Oh my God… It’s full of stars!
For an interesting comparison of the size of planets and stars: click
[takes a few seconds to load]
toyotawhizguy (05:17:57) :
To assume that the solar wind and an interstellar gas cloud would have the same optical qualities because they are both comprised of the same gases is a fallacy.
That was not the assumption or the issue. The interstellar cloud in question is also hot [6000C] and that makes it ionized and comparable to the solar wind.
An amazing picture and not one uber-geek reference to Star Wars. So here it is.(Someone mentioned Romulan though.:))
“Pamela Gray (00:13:11) :
Do I see double Sun’s? These are Suns that rotate around each other.”
Hey, is that a planet orbiting the suns? And wait, there appears to be a young, dirty-blonde haired man staring at the horizon? Oh, and two ships engaging in a battle in orbit? Oh cool, a smaller vessel just launched towards the planet from the smaller of the two battling vessels.
Okay, uber-geekness done. Just a too frackin’ cool picture though.
“Isaac Asimov’s best short story,”Nightfall”, was based entirely on that question.”
Both a short story and a novel. 🙂
@ Mohib (22:52:24)
here is another fine example of pro-am collaboration, which I’ve not seen mentioned here:
http://www.galaxyzoo.org/
Here, ordinary people are asked to help categorize galaxies – because they are better at it than any computer programme.
Great fun – but be warned: its highly addictive …!
Hi Anthony and Team!
We wish you all the best for 2010 from Austria!
Go on with your ecellent work and stay healty.
Oops. Math correction. I should have written:
s = 17.7^1/3
s = 2.6 ly
I used Google math and didn’t at first realize it had divided by 3 instead of taking the cube root. Should have been 17.7^(1/3).
Anyway, that’s 2.6 ly between stars using this approximation. How close to accurate is it?
Carsten Arnholm, Norway (07:23:30) : Perhaps the answer is in this link:
http://www.thunderbolts.info/tpod/2005/arch05/051216m15cluster.htm
There are binary and even ternary star systems out there–where two or three suns orbit around each other. Star systems that have more than three stars are known, but their number declines exponentially.
A few examples of binaries: Sirius (An “A” star and a white dwarf); and Epsilon Aurigae (an eclipsing binary).
A few examples of ternaries: Polaris (one companion star was so close it wasn’t photographed until 2006 w/ Hubble); and Alpha Centauri (a yellow dwarf pair and an outlying red dwarf orbiting the two yellow dwarfs).
I’d just hate to live on a planet orbiting any of these multiple-star systems; days would probably be difficult if not impossible to define and the tides would be chaotic. One sun is enough!
“KlausB (07:07:36) :
[…]
My personal rule of thumb for it: No civilisation will support
more than three builds, …”
Wouldn’t costs come down with each repetition? Or, in other words, with every invention a civilization makes, everything becomes simpler. Say you increase the efficiency of the turbines used in power plants by 0.1 percent point and you have 1000 such power plants. That’s like getting one for free. Now you have the capacity of one powerplant, say 2 GW, for free. Hey, now your civilization can run one synchrotron for free and do materials research with it. And so on.
And this is what is actually happening. (And yes: one synchrotron eats up that much power when its on.)
Just went to this from a Drudge link:
http://www.sciencedaily.com/releases/2009/12/091230184221.htm
No significant rise in CO2 either analzed for last 150 years or for last 5 decades??
Does this mean that if Cap and Trade goes through and atmospheric CO2 goes down, I get some kind of tax refund? Awesomeness!!! 🙂
Fortunately WUWT it is not a confusing globular cluster, it is almost a black hole which sucks all bloggers in it; that is why many posters, I would say the majority of them, in spite of having their own blogs, fall by WUWT gravity which drags them all in. (WUWT could even have some satellite blogs for a fee).
This astronomy issue it is a good new topic, supposing that “global warming” as a discussion issue is about to die frozen.
This new one it is very controversial also, so Good Luck! and
Happy New Year!
DirkH (09:20:11) :
Dirk, costs do only come down when you have multiples to build, especially multiples at the same time. With time lags and technological changes and enhancements, which surely will occure, you allways have a prototype and
the costs of a prototype.
For my rule of thumb, I already factored in a decrease to 1/1000th of the
costs of today, due to technological enhancements.
Awesome. Thanks Anthony and a Happy New Year to you and all the team.
WWUWT — Watts Wayyyy Up With That! Haha. A nice post to conclude the “International Year of Astronomy.”
Astronomy is one of my areas expertise. Here are some replies to the preceding comments…
Mike McMillan: Given the concentration of white and blue stars, you’d probably fry from the UV radiation. .
Actually, most of the stars are red dwarfs. The few blue stars, called “blue stragglers” may be the result of stellar collisions.
Mohib: Amateur astronomers have many, many formal pro-am collaboration relationships….
Here’s another very recent example for your list, featuring yours truly: http://tinyurl.com/ydx3n3v 😀
Robert Wykoff: average distance between stars 17.7 light years.
Gabriel: Actually… 3.2ly on average between stars
Gabriel is correct to note that the density is not uniform. The core is much denser than the fringes. And the total stellar population of M13 is several hundred thousands — not merely 100,000. Figure on spacings < 1 light year in the core.
gtrip: It’s pretty, but can in support life?
Doubtful. Globular clusters are ancient objects formed in the early universe and have very low metalicity (i.e., few elements heavier than Hydrogen and Helium). There has been one planet discovered orbiting a pulsar in another globular cluster, M4. It’s believed to be a Jupiter-like gas giant; perhaps all planets in globular clusters are such.
Pamela Gray: Do I see double Sun’s? These are Suns that rotate around each other.
Globular clusters are certainly chock-full of binary star systems. “Blue stragglers” may be fused binaries. However, most of the pairings you see in the photo are just chance visual alignments — to be expected given such a rich density! (Greetings from the opposite corner of Oregon, BTW)
P Wilson: If the universe is infinite, how can infinity expand on itself?
Food for thought: imagine that the sizes of all objects in the universe are shrinking rather than the spaces between objects expanding — your paradox vanishes, even though the two scenarios are observationally equivalent. 😉
Happy 2010, everyone!
Happy New Year to Anthony and team.
Your efforts are awesome and greatly appreciated.
“Danimals (09:42:00) :
No significant rise in CO2 either analzed for last 150 years or for last 5 decades?? ”
see
http://wattsupwiththat.com/?s=bombshell+from+bristol
“KlausB (09:48:34) :
Dirk, costs do only come down when you have multiples to build, especially multiples at the same time. With time lags and technological changes and enhancements, which surely will occure, you allways have a prototype and
the costs of a prototype. ”
Development costs also come down, think CAD , CAE . Two more examples:
– Leisurely communicating across continents in 2009 without paying a dime. What we do here. Contrast that to 1950.
– The examples earlier in the thread for the achievements of modern day amateur astronomers. I like the pics in http://www.yankee.us.com/images2.html .
Taking pictures like that would have been impossible in 1950 without a huge budget.
Well of course you might see where my argument is leading: Technological Singularity, Vernor Vinge, Ray Kurzweil, all that.
Ah well, it’s a philosophical question. Saying a civilization manages to send out exactly 3 huge spaceships and then perishes is a little arbitrary in my opinion… but thankfully the future of mankind doesn’t depend on our disagreement. You say 3, i say as many as we like. Virgin Galactic Interstellar or something.
Happy New Year 🙂
A theoretical question then:
Could “science” as we know it have started on a planet with 100% cloud cover like Jupiter, Saturn, or Venus?
Nothing to look up and wonder (the sun, stars, and planets) to inspire the first scientists; nothing to “measure” about light or gravity to inspire Einstein’s and the nuclear dynamics of stars.
Chemistry? Geology? Biology? Seems they derived (here) from the astronomers’ curiosity, not vice vesa
Photon without a Higgs,
The universe is believed to be about 13 billion years old, and shaped roughly like a football (no kidding). NASA has some amazing photographs and diagrams on their APOD site, see below.
http://antwrp.gsfc.nasa.gov/apod/ap050925.html
Just went through the comments quickly, but didn’t see this link:
http://antwrp.gsfc.nasa.gov/apod/archivepix.html
There are many, many beautiful and educational photos at the link.
RACookPE1978 (12:04:14) :
A theoretical question then:
Could “science” as we know it have started on a planet with 100% cloud cover like Jupiter, Saturn, or Venus?
First, assume that the species spends some amount of time on land, preferably at dry spots. Some lightning is also helpful.
At some point they will discover fire and how to use it.
Then, if they have any curiosity, they will put stuff in the fire to see what happens. Science will proceed from this beginning.
At some point after they notice that heat rises, they may experiment with hot air balloons. If they have creatures that go off into the sky like birds, they may consider flying devices. Once they realize they can get off the ground, then getting up high enough to touch the sky, the cloud cover, becomes a goal.
And when they find out there is something above their sky…
Note that this would apply to a cloud-covered world period, as neither Jupiter, Saturn, nor Venus seem hospitable to “life as we know it” thus the question is moot for them.
Anthony, Tom in Texas, and everyone who posted photo links: Thanks for this present on the last day of the year. I feel like a kid again, full of wonder. May 2010 bring more wonder to us all.
Thank you, something to use our sense of wonder at this year’s end of our tiny planet, just exquisitely beautiful.
Roger Sowell: The universe is believed to be about 13 billion years old, and shaped roughly like a football (no kidding).
Nooo… it’s not shaped like a football. The map @ http://antwrp.gsfc.nasa.gov/apod/ap050925.html is a Hammer-Aitoff projection. For comparison, see: http://earth.rice.edu/mtpe/geo/geosphere/topics/mapping/40_hammer.html
Robinson (06:16:39) :
> What interests me about globular clusters is why they don’t collapse into a single gigantic star/supernova. Are they orbiting a mutual centre of gravity?
One reason is the same as to why the Earth doesn’t collapse into the Sun – our motion relative the sun isn’t aimed at the Sun. (If it were a right angle all the time, we’d have a circular orbit. It isn’t, so we have an elliptical orbit.)
If two stars in a cluster approach each other, they follow highly eccentric, nearly parabolic paths and (nearly always) miss each other. Sometimes a star gains enough kinetic energy from a couple close approaches so that it’s kicked out of the cluster. The lost of energy makes the remaining stars pack a little more closely together.
For some real fun, download the free software found at http://www.stellarium.org/.
You can view the stars as they appear from your locale and time. You can also locate prominent objects such as M13.
This object is also known as the Hercules Nebula and can be easily seen with the unaided eye in dark skies. You’ll need binoculars or telescope within the city.
Hercules is setting now and won’t be visible until about an hour before dawn.
You’ll be able to easily see tonight’s Blue Moon, except in the eastern hemisphere when January 2010 will have two full moons.
See http://www.earthsky.org/tonighthome/2009-12-31/url
Thanks Jack, I plan to do a post on Stellarium, a wonderful program.
Actually, for those interested … we don’t know the shape of the universe or if it is infinite. We only know that space is expanding and what we see in our ‘light speed event horizon’ arose from a very dense region of space. Einstein’s Theory suggests a singularity … I’m just getting into what modified gravity (MOG) says about the beginning of what we see in the light spectrum (not just visible).
Happy New Year, Anthony and all those contributors to WUWT! You are intellectual relief in a Machiavellian Realpolitik Zeitgeist world.
Re: Apparent expansion of the Universe.
The explanation of this purely observational phenomenon is written on every right rear view car mirror in the United States.
Beautiful star cluster, by the way. I made it a screen desktop background.
I wish good health and prosperity to every rationally thinking person on our healthy and prosperous planet!
WE SHALL OVERCOME SOME NIGHT
HAPPY NEW YEAR 2010!
Whether anti or pro AGW, scientist or other walk of life
May the road rise up to meet you.
May the wind be always at your back.
May the sun shine warm upon your face;
the rains fall soft upon your fields and until we meet again,
may God hold you in the palm of His hand.
For those with clear dark night skies, log on to http://www.heavens-above.com/
The sky, satellites, comets can be checked from your location on earth. I find the satellite pass times quite accurate. A fun observation not mentioned is to watch the docking/undocking of the Shuttle from the ISS.
NASA should stick to what it does best, space exploration.
Those of you who don’t know about this free software to facilitate star gazing might enjoy having it.
http://www.skyviewcafe.com/
ORIGINAL SOURCE(S)
http://www.nasa.gov/multimedia/imagegallery/image_feature_1552.html
http://hubblesite.org/newscenter/archive/releases/2008/40/
http://www.spacetelescope.org/images/html/opo0840a.html
A nice video on M13 (and other globular clusters).
with more here.
http://astronomy2009.nasa.gov/topics_jun.htm
Ric Werme (06:54:27) :
I’ve long wondered what the night sky looks like to an owl.
Probably the same way it looks through Night Vision Goggles — “amazing.”
*******
Erik Anderson (09:50:44) :
gtrip: It’s pretty, but can in support life?
Doubtful. Globular clusters are ancient objects formed in the early universe and have very low metalicity (i.e., few elements heavier than Hydrogen and Helium). There has been one planet discovered orbiting a pulsar in another globular cluster, M4. It’s believed to be a Jupiter-like gas giant; perhaps all planets in globular clusters are such.
********
Erik I’d agree, rocky (iron & silicon) planets may be rare to almost non-existent in an ancient dust & gas-free globular. And so might be life, unless it can develop on icy moons of gas-giants.
beautiful pictures, love it