Starship Asterisk*

It's just a dirty scope, Hansen. You can check SDSS survey data at 12:27:24.86 +13:03:16.8 and there's nothing there.

I'm wondering if anyone noticed what appears to be a pretty interesting lensing event in the upper-left corner of the picture. It is small, but in a dark location and encircles a dim blob that is clearly a very, very distant galaxy. The lensed image is almost an arc of 180 degrees around that dim galaxy, and this (apparently) lensed object appears to have more detail than just another faint, spherical blob - it looks like it is a background galaxy being magnified significantly. And the fact that it is being lensed by this very faint, clearly singular, dim blob would tend to indicate that that blob doing the lensing is very, very massive. Also, the lensing is very sharp, seemingly indicating that it might, just possibly, be so distant and violently lensed that very small changes in relative position of the lensing blob may cause a visible change in the lensed image of the background galaxy - meaning that periodic re-imaging might lead to a visible change in the lensed shape of the distant galaxy.... Now that is a "movie" I would like to see.

The object doing the apparent lensing is located at (in the hi-res image APOD links to - the 8000 x 6074 pixel image) pixel (1523,893). The apparent lensed arc runs from pixel (1540,882) to (1503,923). It looks like a hair fell onto a photographic plate - and maybe that really is what it is - but if that filament is really out there and really is a lensing event, it's a pretty incredible one.

Another tantalizing explanation is that what I've called the blob (galaxy?) doing the apparent lensing might not actually be doing the lensing - it is significantly off-center relative to the lensed arc. And if it isn't doing the lensing, then you have an incredibly large amount of mass there doing the lensing - but it is completely dark. Is it a black hole?

Suppose it really is a black hole, and the faint blob is just an off-center (ie not significantly lensed) background galaxy, or is a foreground dwarf galaxy or cluster. Where in the line of sight is the black hole? Could it be a black hole that was flung out of the distended, bright Markarian galaxy just to the lower left of it in this image? That galaxy is clearly recovering from a galactic collision - and/or is experiencing tidal forces from something.

I checked the 2007 APOD image of Markarian's Eyes linked to in this one's description - http://apod.nasa.gov/apod/ap070608.html - it doesn't quite have the resolution to show if the lensed arc is present or not. I'm very curious to hear if any other images show the arc, and if so, is it changing at all?

That 2007 APOD, however, shows slightly better what appear to be large molecular clouds darkening regions of the picture. Note another apparent lensing center-of-mass roughly near (1543,421) and/or (1522,507) - the distant galaxies at (1537,292), (1670,342), (1802,654), and (1294,497) all appear to be lensed. The center of that lensing event is a strangely dark field that seems to have significantly less background light noise than most of the other "empty"/"black" areas of this photo. It's as if there is a gigantic molecular cloud there centered around (1627,479), a dark circle with a diameter of almost 200 pixels where significantly fewer distant light sources are present, compare to most other fields in the photo. This "giant dark cloud" seems to continue (or have companions) - such as (1830,1406). There are a quite a few more where it seems the distant background galaxies have been uniformly shaded. Is that an artifact introduced later? Or just a coincidence? It looks to me like there really is some kind of cloud blocking the view (maybe it's a nearby cloud...).

Some more squiggles that - if they are actually more lensing events - would be extraordinary to monitor for changes: (2574,5926), (2709,5945) - this one has a circular curve to it like the larger one - implying a very compact (in radial diameter), dim mass..., (1035,2933).

The seemingly dark mass apparently doing the lensing here - over vast parts of the image - may suggest the presence of a large quantity of dark matter, which would also explain the co-location of so many galaxies. Suppose those dark or shady regions are relatively dense concentrations of dark matter, flung around chaotically during the recent galactic collision. Even as such a collection of dark matter can facilitate lensing and amplification of distant galaxies, it might also explain the darkness of these regions if the dark matter is essentially defracting much of the other light (those not being amplified along our sight-line) away from our sight-line - just as happens when you focus a beam of light onto a surface using a lens - the lens concentrates much of the light to a point, but all around that point is a dark shadow being apparently cast by the lens - but, in fact, the lens is just shifting light to the focal point, and scattering all other mis-aligned rays. If that's what's going on here, it suggests that detailed, repeated observations of those dark fields of (possibly) concentrated, high-velocity dark matter might be a location where otherwise infrequent dark-matter collisions are happening at a higher rate. Maybe we can catch a few photons and shed some light on what dark matter is?

Thanks, Ann.

[quote="Craine"]I guess the confusion is with temperature vs. energy content. The temperature of the Sun's corona is very high, but it is so tenuous that the energy content of say a cubic meter of corona is very low. While the energy content of a cubic meter of the Sun's photosphere is very high, even at a temperature of 'only' 5800 K.

You'd feel cold in the corona. You'd feel nothing in the photosphere...cause you'd be dead.[/quote]
Ignoring impact (space weathering) forms of energy dissipation, and only looking at average-power as the "heating" mechanism, the solar-wind at 1 AU is a good example to see the difference.

[attachment=0]Solar Wind Properties at 1 AU.JPG[/attachment]
Reducing the problem to simple numbers: Proton Velocity ≈ 400km/sec; Proton Density ≈10/cm[sup]3[/sup], [u]Proton Temperature ≈ 30,000 K[/u]
=> Energy Flux Density ≈ 1.5 erg cm[sup]-2[/sup] sec[sup]-1[/sup][color=#0000FF][size=130] => 1.5 mW/m[sup]2[/sup][/size][/color]

Assuming all this power goes to heat, the magnitude is inconsequential to the total incident solar radiation at ≈ 1400 W/m[sup]2[/sup] [color=#0000FF][size=130](~10[sup]-6[/sup])
[/size][/color]This is why even routine (space walking) exposure is not an issue in this rarefied, very hot plasma evironment. However, hanging one's space suit out to degas :) for decades would be problem. (Even here, deep UV is likely the biggest problem for material degradation.)

The exchange between Tomatoherd and Chris has been quite educational , thanks guys!

I guess the confusion is with temperature vs. energy content. The temperature of the Sun's corona is very high, but it is so tenuous that the energy content of say a cubic meter of corona is very low. While the energy content of a cubic meter of the Sun's photosphere is very high, even at a temperature of 'only' 5800 K.

You'd feel cold in the corona. You'd feel nothing in the photosphere...cause you'd be dead.

[quote="tomatoherd"][quote="Chris Peterson"]Yes, a liquid could be at 212°F in a gaseous environment that is at 2100°F.[/quote]
Yes, I know that, but even in an oven at 2100 K it would soon boil off and be gas. I meant long term. How can the sun's surface be 5000 k in a medium that is 30 million K? It couldn't. there cannot be dual temperatures for a given locus. [/quote]
Yes, there can.

Water isn't the best example, because it evaporates when it's at a low pressure. But ignoring that, you could have a glass of water in a very low pressure medium heated to thousands of degrees and that water will never boil. The Sun [i]is[/i] sitting in a higher temperature medium than its surface temperature, as the coronal temperature is around a million degrees. So the surface of the Sun is happily at 5800 K while its surrounding atmosphere is several orders of magnitude hotter.

[quote]Anyway, if one could actually feel cold in a 'hard vacuum' w/ a temp of 30 million K, isn't it sorta useless for us to refer to temperature? (And what would thermometers measure? I'm sure it would take a special one to measure that occasional baryon, and the measurement itself would change things, no?) So what good is it to speak of temperatures of very rarified media? Apparently none.[/quote]
Why is the notion of temperature useless simply because the rate of energy transfer happens to be low? Temperature is a measure of the kinetic energy of the system, and that's incredibly useful. It explains why we see UV emissions in nearly empty space, for example. There are temperature measurement devices designed for working in near vacuums. And certainly, we can measure temperature simply by looking at emitted radiation in many cases.

Beautiful image!

Is Dark Matter the glue that holds visible matter in place?

[quote="Chris Peterson"][quote="tomatoherd"].

Yes, a liquid could be at 212°F in a gaseous environment that is at 2100°F.[/quote][/quote]

Yes, I know that, but even in an oven at 2100 K it would soon boil off and be gas. I meant long term. How can the sun's surface be 5000 k in a medium that is 30 million K? It couldn't. there cannot be dual temperatures for a given locus.

Anyway, if one could actually feel cold in a 'hard vacuum' w/ a temp of 30 million K, isn't it sorta useless for us to refer to temperature? (And what would thermometers measure? I'm sure it would take a special one to measure that occasional baryon, and the measurement itself would change things, no?) So what good is it to speak of temperatures of very rarified media? Apparently none.

[quote="Craine"]This is a close-up of M84, in negative colors and enhanced contrast to bring out some detail.. And yes, it does show a cone-shaped thingie.

However, if you look closely at the star to the bottom right, and the galaxy top right, you will see a similar vertical effect.
So, I agree with Geckzila, it is probably an image artifact.[/quote]
As the image author noted, it's just a blooming spike that hasn't been totally removed. Lots of stars have them, and you can see hints of them around other extended sources, as well.

This is a close-up of M84, in negative colors and enhanced contrast to bring out some detail.. And yes, it does show a cone-shaped thingie.
[attachment=0]m84.jpg[/attachment]

However, if you look closely at the star to the bottom right, and the galaxy top right, you will see a similar vertical effect.
So, I agree with Geckzila, it is probably an image artifact.

[quote="tomatoherd"]Okay, maybe no one has time to play physics teacher, but I don't understand this: Followed the second Virgo link to Wiki's Virgo Cluster article. Then under intracluster medium section, followed first link to intracluster medium.
1) what gives: is the space between those galaxies really 30 million Kelvin, while space outside of clusters in is near absolute zero??? And aren't we in the Local Group also in a cluster, and if so, does our intracluster medium also have a horribly high temperature, and if so, why does earth and air and water exist?????
2) never grasped this: temperature is mediated by particles; kinetic energy/particle motion IS temperature. So how can such a rarified medium (second link describes a typical density as 1 baryon per thousand cubic centimeters, and a 'mean free path' of particles close to a light year before collision) mediate such high temperatures??? If we put our hand into the Virgo Cluster intracluster medium, would it feel hot? (or vaporize due to heat, or due to vacuum). How could it feel hot if only a couple of baryons were hitting it at a time????
3) how do stellar processes even function in an alleged ICM at 30 million K? The suns photosphere and chromosphere are only at 3 to 5 thousand K. But you can't be that much lower if your milieu is a thousand times hotter. Can a pot of water be boiling at 212 F in a kitchen whose ambient temp is 2100 F ????
HELP!!![/quote]
The temperature of a gas is determined by the kinetic energy of the gas particles. In a rarified medium, the individual particles can have very high energies (that is, they can be hot) even though the total energy of the medium is low. For example, where the ISS orbits, the temperature of the medium is around 2000°C. But the ISS doesn't melt, and people can be outside with basic space suits. And that's because there are so few particles that almost no energy gets transferred. The medium is simply too thin to efficiently heat anything up. It's the same all over the Universe. Imaging in certain bands (like x-rays) shows us very, very hot material. Millions of degrees, sometimes. But we're looking at something that represents a very hard vacuum. So if you were present in that region, you would almost certainly freeze, because you'd be losing heat radiatively far faster than you'd gain it from the occasional collision with a hot atom.

Yes, a liquid could be at 212°F in a gaseous environment that is at 2100°F.

Okay, maybe no one has time to play physics teacher, but I don't understand this: Followed the second Virgo link to Wiki's Virgo Cluster article. Then under intracluster medium section, followed first link to intracluster medium.
1) what gives: is the space between those galaxies really 30 million Kelvin, while space outside of clusters in is near absolute zero??? And aren't we in the Local Group also in a cluster, and if so, does our intracluster medium also have a horribly high temperature, and if so, why does earth and air and water exist?????
2) never grasped this: temperature is mediated by particles; kinetic energy/particle motion IS temperature. So how can such a rarified medium (second link describes a typical density as 1 baryon per thousand cubic centimeters, and a 'mean free path' of particles close to a light year before collision) mediate such high temperatures??? If we put our hand into the Virgo Cluster intracluster medium, would it feel hot? (or vaporize due to heat, or due to vacuum). How could it feel hot if only a couple of baryons were hitting it at a time????
3) how do stellar processes even function in an alleged ICM at 30 million K? The suns photosphere and chromosphere are only at 3 to 5 thousand K. But you can't be that much lower if your milieu is a thousand times hotter. Can a pot of water be boiling at 212 F in a kitchen whose ambient temp is 2100 F ????
HELP!!!

It is blooming on M84 core on the Subaru data partially removed with HST data

[quote="sunlight"]M84 seems to have a cone shaped "thing" right above the nucleus. Any idea any one?[/quote]
Don't see it in any other images of the same galaxy. Gonna go with optical artifact of some sort.

M84 seems to have a cone shaped "thing" right above the nucleus. Any idea any one?

[quote="starsurfer"]The only thing this image is missing[/quote]
Is nothing. It's a fabulous image.

[quote="NCTom"]What is the estimated distance between the galaxies at the heart of the Virgo Cluster? Anything like the Milky Way and Andromeda?[/quote]

The galaxies in the center of the Virgo Cluster are much closer together than the Milky Way and Andromeda. For our own galaxy and Andromeda, the distance between the luminous disks is about ~20 galaxy diameters. But for the galaxies in the center of the Virgo Cluster, the average distance between the luminous disks or the luminous elliptical bodies may not be more than ~5 galaxy diameters.

Ann

What is the estimated distance between the galaxies at the heart of the Virgo Cluster? Anything like the Milky Way and Andromeda?

The only thing this image is missing is a massive Ha exposure that shows rarely seen [url=http://www.noao.edu/outreach/press/pr08/pr0807.html]ionized filaments of gas[/url] between the galaxies, I don't think these have ever been revealed in an amateur image. [url=http://www.cosmotography.com]Jay GaBany[/url] or [url=http://www.imagingdeepsky.com]Ken Crawford[/url] could do an awesome megamosaic!

Also this is my [url=http://www.robgendlerastropics.com/NGC1333NM.html]1333rd[/url] post!! :D :D :D

[quote="APOD Robot"]includes bright [url=http://apod.nasa.gov/apod/ap000311.html]Messier[/url] galaxies such as [url=http://apod.nasa.gov/apod/ap070608.html]Markarian's Eyes[/url] on the upper left, [url=http://apod.nasa.gov/apod/ap080425.html]M86[/url] just to the upper right of center, [url=http://en.wikipedia.org/wiki/Messier_84]M84[/url] on the far right, as well as spiral galaxy [url=http://apod.nasa.gov/apod/ap020603.html]NGC 4388[/url] at the bottom right.
[/quote]
The Eyes are catalogued in the NGC as NGC 4435 and NGC 4438?

No wonder bystander finds so many things to post about. With those eyes, he sees almost everything. :yes:

I can see that bystander is checking in [url=http://apod.nasa.gov/apod/ap070608.html](Eyes galaxies)[/url]. :yes:

Ann

Interesting group....

"Deeeeep in the heaaaart of VIRGO...." :lol2:

:---[===] *

[url=http://apod.nasa.gov/apod/ap150407.html][img]http://apod.nasa.gov/apod/calendar/S_150407.jpg[/img] [size=150]In the Heart of the Virgo Cluster[/size][/url]

[b] Explanation: [/b] The [url=http://apod.nasa.gov/apod/ap110422.html]Virgo Cluster of Galaxies[/url] is the closest cluster of galaxies to our [url=http://apod.nasa.gov/apod/milky_way.html]Milky Way Galaxy[/url]. The [url=http://en.wikipedia.org/wiki/Virgo_Cluster]Virgo Cluster[/url] is so close that it spans more than 5 [url=http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/angular.html]degrees[/url] on the sky - about 10 times the angle made by a [url=http://apod.nasa.gov/apod/ap040829.html]full Moon[/url]. With its heart lying about 70 million light years distant, the [url=http://messier.seds.org/more/virgo.html]Virgo Cluster[/url] is the nearest [url=http://www.astr.ua.edu/white/mug/cluster/clusters.html]cluster of galaxies[/url], contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the [url=http://en.wikipedia.org/wiki/Local_Group]Local Group of Galaxies[/url] surrounding our [url=http://apod.nasa.gov/apod/ap080606.html]Milky Way Galaxy[/url]. [url=http://starmatt.com/gallery/astro/virgo_cluster.html]The cluster[/url] contains not only galaxies filled with stars but also [url=http://apod.nasa.gov/apod/ap960419.html]gas[/url] so hot it glows in [url=http://chandra.harvard.edu/xray_astro/xrays.html]X-rays[/url]. Motions of [url=http://science.nasa.gov/astrophysics/focus-areas/what-are-galaxies/]galaxies[/url] in and around clusters indicate that they contain more [url=http://chandra.harvard.edu/xray_astro/dark_matter.html]dark matter[/url] than any visible matter we can see. [url=http://www.astrobin.com/166281/0/]Pictured above[/url], the heart of the [url=http://en.wikipedia.org/wiki/Virgo_Cluster]Virgo Cluster[/url] includes bright [url=http://apod.nasa.gov/apod/ap000311.html]Messier[/url] galaxies such as [url=http://apod.nasa.gov/apod/ap070608.html]Markarian's Eyes[/url] on the upper left, [url=http://apod.nasa.gov/apod/ap080425.html]M86[/url] just to the upper right of center, [url=http://en.wikipedia.org/wiki/Messier_84]M84[/url] on the far right, as well as spiral galaxy [url=http://apod.nasa.gov/apod/ap020603.html]NGC 4388[/url] at the bottom right.

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