To see the plot, read the paper (PDF), not the article. Figure 4 does not look like a square to me. Figure 7 has some squarish shapes drawn over the plot, but it is not highly convincing. Further, these squarish orbits appear in the inner parts of the Galaxy, not the outer shape as one might assume. Orbital shapes change with radius as different gravitational resonances dominate at different distances.
We agree. Our current system does not allow us to release multiple formats in a simple manner. We chose red/cyan anaglyph as a test case. We are quite glad to see that there is demand for a side-by-side version as well as a YouTube version. For the slashdot crowd, conversion of formats and/or download and play through special software is no problem. The general public is the vast majority of our visitors and they generally just want to push play in the browser. What I suspect would make our website folks happiest is if we could employ something like the YouTube 3D player on our web pages. Your comments will help us make arguments for better 3D support. Thank you.
Thanks for the info, Joseph. You clarified the most important point - that the TV is switched into 3D mode separately from Media Play opening the file and starting it. We will have access to a 3D HDTV for testing shortly (it is also a Samsung, which is why I had looked into Media Play). When ready, I will be glad to post a version for you and others to download. I'll post the link as a comment to this thread and also see if the folks who do the YouTube channel will post it there. Thank you very much for your feedback.
We are interested in producing files that folks could watch directly on their 3D HDTV via USB, but have not figured out the encoding to use. In looking at the Samsung Media Play supported video formats, none of them jump out at me as being side-by-side, top-bottom, or other obviously 3D aspect ratios. They are all listed as 1920x1080 (with a couple 800x600). Hence, one could do a 1/2 width side-by-side or 1/2 height top-bottom, but not a full resolution or the Blu-ray 3D format of 1920x2205 at 24 fps. Have you done 3D off a USB stick on your Samsung? What is the encoding that tells the TV to activate 3D mode? How does the TV know a file is 1/2 width side-by-side 1920x1080 vs a normal 1920x1080 movie?
No, we did not attempt to include relativistic effects. If we were creating a video to explain special/general relativity, we would include them. Otherwise, such effects would be too confusing for the average viewer, especially since this movie has no narration.
Yes, of course the camera separation is much wider than human eye separation. The camera motion is also probably faster than the speed of light. As you correctly infer, scientifically accurate visualizations of what the human eye would see moving at currently achievable speeds would look no different than the original Hubble image. What would be the point in releasing such a visualization?
Thank you for your comments on 3D formats. We did not feel that enough of the public has 3D hardware today, but a reasonable number might have anaglyph glasses. If we do future projects, we will increase the formats as appropriate.
The visualization does uses separate left and right cameras. However, I forgot to mention in the posting that the "3D" is mostly "2.5D". We have no information about what the backside of the nebula looks like, so we could only do full 3D modeling if we artistically created volumes and pixels that Hubble does not observe. We did some of that for the "Hubble 3D" film, but did not invest such time on this project. We did sculpt the front side of the clouds in the nebula into landscapes, but the camera path stays mostly in front, so the sculpting is not that obvious. We are testing to see how much effort is required to get "enough" immersion.
Yes, that line in the post was intentionally ironic. We did not trumpet the 3D in the press release for the general public, but if the post made it to slashdot we would be loud to the tech savvy audience who could give us the best feedback.
100 light-years = 1 quadrillion kilometers -- You want a 1 meter resolution at that distance, so you need an angular resolution alpha, where tan(alpha) = 1 / 10^18 --> alpha = 5.7 x 10^-17 degrees
Let's use Hubble as a scaling proxy. It has a 2.5 meter mirror and 1/20th of an arc second resolution. Converting units, that resolution is 1 / (20*60*60) = 1.4 x 10^-5 degrees. Now, simply scale to get the desired resolution and you have the diameter of the mirror = 2.5 * 1.4 x 10^-5 / 5.7 x 10^-17
The diameter you want is 614 million kilometers, or more than 4 times the distance between Earth and the Sun. Good luck building that.
Adaptive optics works great at infrared wavelengths. It does not (yet) do well at visible wavelengths. Even the 2.5 meter mirror of Hubble has better resolution at visible wavelengths than the 10 meter Keck mirror due to atmospheric blurring. Further, adaptive optics is only effective over small fields of view (such as a single star and planet). One can not take a wide field view of a nebula or a galaxy and get a high resolution adaptive optics view over the whole field.
Yes, the text is wrong. There are several methods for detecting the presence of an exoplanet, though the "wobble" (aka radial velocity) method has so far been the dominant one. One can also other methods like transits (like Kepler), astrometry, gravitational lensing, and pulsar timing. After Kepler has completed its mission, there will likely be more planets detected by transits than by any other method.
That depends on what you mean by "a really decent" image. We can see surface features on Pluto, albeit still a very fuzzy view. These exoplanets are unresolved - we can see they are there, but we can see absolutely no details. Further, recognize that a Jupiter-size planet is over 100,000 km in diameter,
while the largest Kuiper Belt objects (KBOs, which includes Pluto) are at best 3,000 km. Surface area goes as the square of the diameter, so you can see that the amount of light reflected will be vastly larger for a giant planet than for even the biggest KBOs. Plus KBOs tend to be rather dark and reflect little of the light that hits them (low albedo). BUT, this will change in 2015 when New Horizons gets to the Pluto/Charon system and shows the details.
There are several direct images of exoplanets available. Hubble took one of a planet around Fomalhaut, which was announced the same day that Keck announced three planets around HR 8799 (Nov 13, 2008). The next week, ESO announced a possible planet around Beta Pictoris, which has recently been confirmed.
What these folks at Gemini are saying is that they announced a possible direct image earlier in 2008, which they have now confirmed, so theirs was really the first. It is a game of "who got the first direct image of a planet around another star?".
It doesn't really matter, but it is very cool that we can now directly see not only the 8 planets in our solar system, but also at least 6 more in other solar systems. At some pivotal point in the near future we will have more pictures of planets outside our solar system than within it!
Amongst professional astronomers (which includes me), Pluto is generally not considered a planet. It is the largest member of the Kuiper Belt. It is historical accident that Pluto was discovered almost 50 years before the second Kuiper Belt object, Charon, in 1978. The third KBO was found in 1993. Since then, over 700 other KBOs have been found, several of which rival Pluto in size.
What we have here is one that could be larger than Pluto. This is not unexpected, but has been predicted ever since we started discovering KBOs in serious numbers. There is always a distribution of sizes, and Pluto lies near the upper end, but it is unlikely that it is the largest, and even less likely that it would be distinctly larger than the rest of the population.
To call Pluto a planet is to create a category of "ice planets" which contains only one object. That is scientifically silly. To call it a Kuiper Belt Object fits it in with a family of other objects whose characteristics in composition, orbit size, orbit shape, orbit inclination, companions, etc are shared amongst the group. That is a scientific classification.
The solar system does not contain "the Sun and 9 planets" as so many of us incorrectly learned. Rather, it contains 6 families: a star, the rocky planets, the asteroid belt, the gas giant planets, the Kuiper belt, and the Oort cloud. Each of these families shares common characteristics that are the basis for this classification. Pluto, and this new discovery, fit squarely in the Kuiper belt.
Now for the truth about planets. The IAU, which governs these things, has no official definition of what constitutes a planet. There is a reasonable upper limit in mass (i.e., not so larger as to create fusion at it core), but there is no lower limit. Most astronomers would say that a reasonable idea would be large enough for gravity to make it spherical (or close to, like Earth). However, then other KBOs and asteroids qualify as planets. You simply can't come up with a rigorous definition that includes Pluto and excludes the others unless you work customize your definition in a manner that is not scientific.
This will not be the last big KBO. There will be several more. These are exciting times as we discover more and more about our own backyard.
No, dark matter in filaments does not have to imply lensing.
To get gravitational lensing, one has to have a sufficient integrated density along the line of sight. It is fair to surmise that looking "down the pipe" of a filament might produce enough integrated density to produce lensing, but it is not a necessary consequence.
I haven't heard of any lensing based on filament structures, but the folks who do what is called "weak lensing" might have some statistical arguments that can correlate their results with the likely (or unlikely) presence of filaments.
The main result I remember associated with filaments is the apparent clumpiness of the galaxy distribution on small scales. If you've got a lot of linear structures where galaxies form, then you get more super-positions of galaxies than would occur in a random distribution. Such arguments can explain the over-numerous of Hickson Compact Groups of Galaxies.
For those who would like to know what a "filament" might look like, you can see my visualization of large
scale structure in the universe called "Cosmic Cruising 2" at http://terpsichore.stsci.edu/~summers/viz/cosmic_c ruising_2/. Please note that this visualization is not from observed galaxy data, but rather from a supercomputer simulation that has roughly the same statistical properties as the real universe.
Slashdot Mirror
To see the plot, read the paper (PDF), not the article. Figure 4 does not look like a square to me. Figure 7 has some squarish shapes drawn over the plot, but it is not highly convincing. Further, these squarish orbits appear in the inner parts of the Galaxy, not the outer shape as one might assume. Orbital shapes change with radius as different gravitational resonances dominate at different distances.
The software used on this project is mainly Maya, Photoshop, ImageMagick, and perl scripts on both Linux and OS X.
We agree. Our current system does not allow us to release multiple formats in a simple manner. We chose red/cyan anaglyph as a test case. We are quite glad to see that there is demand for a side-by-side version as well as a YouTube version. For the slashdot crowd, conversion of formats and/or download and play through special software is no problem. The general public is the vast majority of our visitors and they generally just want to push play in the browser. What I suspect would make our website folks happiest is if we could employ something like the YouTube 3D player on our web pages. Your comments will help us make arguments for better 3D support. Thank you.
Thanks for the info, Joseph. You clarified the most important point - that the TV is switched into 3D mode separately from Media Play opening the file and starting it. We will have access to a 3D HDTV for testing shortly (it is also a Samsung, which is why I had looked into Media Play). When ready, I will be glad to post a version for you and others to download. I'll post the link as a comment to this thread and also see if the folks who do the YouTube channel will post it there. Thank you very much for your feedback.
We are interested in producing files that folks could watch directly on their 3D HDTV via USB, but have not figured out the encoding to use. In looking at the Samsung Media Play supported video formats, none of them jump out at me as being side-by-side, top-bottom, or other obviously 3D aspect ratios. They are all listed as 1920x1080 (with a couple 800x600). Hence, one could do a 1/2 width side-by-side or 1/2 height top-bottom, but not a full resolution or the Blu-ray 3D format of 1920x2205 at 24 fps. Have you done 3D off a USB stick on your Samsung? What is the encoding that tells the TV to activate 3D mode? How does the TV know a file is 1/2 width side-by-side 1920x1080 vs a normal 1920x1080 movie?
No, we did not attempt to include relativistic effects. If we were creating a video to explain special/general relativity, we would include them. Otherwise, such effects would be too confusing for the average viewer, especially since this movie has no narration.
Thank you for your comments on 3D formats. We did not feel that enough of the public has 3D hardware today, but a reasonable number might have anaglyph glasses. If we do future projects, we will increase the formats as appropriate.
The visualization does uses separate left and right cameras. However, I forgot to mention in the posting that the "3D" is mostly "2.5D". We have no information about what the backside of the nebula looks like, so we could only do full 3D modeling if we artistically created volumes and pixels that Hubble does not observe. We did some of that for the "Hubble 3D" film, but did not invest such time on this project. We did sculpt the front side of the clouds in the nebula into landscapes, but the camera path stays mostly in front, so the sculpting is not that obvious. We are testing to see how much effort is required to get "enough" immersion.
Yes, that line in the post was intentionally ironic. We did not trumpet the 3D in the press release for the general public, but if the post made it to slashdot we would be loud to the tech savvy audience who could give us the best feedback.
The 2D version of the movie is available as well: http://hubblesite.org/newscenter/archive/releases/2010/29/video/a/
OK - Here's the math ...
100 light-years = 1 quadrillion kilometers -- You want a 1 meter resolution at that distance, so you need an angular resolution alpha, where tan(alpha) = 1 / 10^18 --> alpha = 5.7 x 10^-17 degrees
Let's use Hubble as a scaling proxy. It has a 2.5 meter mirror and 1/20th of an arc second resolution. Converting units, that resolution is 1 / (20*60*60) = 1.4 x 10^-5 degrees. Now, simply scale to get the desired resolution and you have the diameter of the mirror = 2.5 * 1.4 x 10^-5 / 5.7 x 10^-17
The diameter you want is 614 million kilometers, or more than 4 times the distance between Earth and the Sun. Good luck building that.
Take a look at the ATLAST concept for a telescope that could be launched in the 2025-2030 timeframe. It comes closest to what you are looking for.
Adaptive optics works great at infrared wavelengths. It does not (yet) do well at visible wavelengths. Even the 2.5 meter mirror of Hubble has better resolution at visible wavelengths than the 10 meter Keck mirror due to atmospheric blurring. Further, adaptive optics is only effective over small fields of view (such as a single star and planet). One can not take a wide field view of a nebula or a galaxy and get a high resolution adaptive optics view over the whole field.
Yes, the text is wrong. There are several methods for detecting the presence of an exoplanet, though the "wobble" (aka radial velocity) method has so far been the dominant one. One can also other methods like transits (like Kepler), astrometry, gravitational lensing, and pulsar timing. After Kepler has completed its mission, there will likely be more planets detected by transits than by any other method.
That depends on what you mean by "a really decent" image. We can see surface features on Pluto, albeit still a very fuzzy view. These exoplanets are unresolved - we can see they are there, but we can see absolutely no details. Further, recognize that a Jupiter-size planet is over 100,000 km in diameter, while the largest Kuiper Belt objects (KBOs, which includes Pluto) are at best 3,000 km. Surface area goes as the square of the diameter, so you can see that the amount of light reflected will be vastly larger for a giant planet than for even the biggest KBOs. Plus KBOs tend to be rather dark and reflect little of the light that hits them (low albedo). BUT, this will change in 2015 when New Horizons gets to the Pluto/Charon system and shows the details.
There are several direct images of exoplanets available. Hubble took one of a planet around Fomalhaut, which was announced the same day that Keck announced three planets around HR 8799 (Nov 13, 2008). The next week, ESO announced a possible planet around Beta Pictoris, which has recently been confirmed. What these folks at Gemini are saying is that they announced a possible direct image earlier in 2008, which they have now confirmed, so theirs was really the first. It is a game of "who got the first direct image of a planet around another star?". It doesn't really matter, but it is very cool that we can now directly see not only the 8 planets in our solar system, but also at least 6 more in other solar systems. At some pivotal point in the near future we will have more pictures of planets outside our solar system than within it!
Amongst professional astronomers (which includes me), Pluto is generally not considered a planet. It is the largest member of the Kuiper Belt. It is historical accident that Pluto was discovered almost 50 years before the second Kuiper Belt object, Charon, in 1978. The third KBO was found in 1993. Since then, over 700 other KBOs have been found, several of which rival Pluto in size.
What we have here is one that could be larger than Pluto. This is not unexpected, but has been predicted ever since we started discovering KBOs in serious numbers. There is always a distribution of sizes, and Pluto lies near the upper end, but it is unlikely that it is the largest, and even less likely that it would be distinctly larger than the rest of the population.
To call Pluto a planet is to create a category of "ice planets" which contains only one object. That is scientifically silly. To call it a Kuiper Belt Object fits it in with a family of other objects whose characteristics in composition, orbit size, orbit shape, orbit inclination, companions, etc are shared amongst the group. That is a scientific classification.
The solar system does not contain "the Sun and
9 planets" as so many of us incorrectly learned. Rather, it contains 6 families: a star, the rocky planets, the asteroid belt, the gas giant planets, the Kuiper belt, and the Oort cloud. Each of these families shares common characteristics that are the basis for this classification. Pluto, and this new discovery,
fit squarely in the Kuiper belt.
Now for the truth about planets. The IAU, which
governs these things, has no official definition of what constitutes a planet. There is a reasonable upper limit in mass (i.e., not so larger as to create fusion at it core), but there is no lower limit. Most astronomers would say that a reasonable idea would be large enough for gravity to make it spherical (or close to, like Earth). However, then other KBOs and asteroids qualify as planets. You simply can't come up with a rigorous definition that includes Pluto and excludes the others unless you work customize your definition in a manner that is not scientific.
This will not be the last big KBO. There will be several more. These are exciting times as we discover more and more about our own backyard.
To get gravitational lensing, one has to have a sufficient integrated density along the line of sight. It is fair to surmise that looking "down the pipe" of a filament might produce enough integrated density to produce lensing, but it is not a necessary consequence.
I haven't heard of any lensing based on filament structures, but the folks who do what is called "weak lensing" might have some statistical arguments that can correlate their results with the likely (or unlikely) presence of filaments.
The main result I remember associated with filaments is the apparent clumpiness of the galaxy distribution on small scales. If you've got a lot of linear structures where galaxies form, then you get more super-positions of galaxies than would occur in a random distribution. Such arguments can explain the over-numerous of Hickson Compact Groups of Galaxies.
For those who would like to know what a "filament" might look like, you can see my visualization of large scale structure in the universe called "Cosmic Cruising 2" at http://terpsichore.stsci.edu/~summers/viz/cosmic_c ruising_2/. Please note that this visualization is not from observed galaxy data, but rather from a supercomputer simulation that has roughly the same statistical properties as the real universe.