These data were taken in the mid-infrared, where the contrast between the star and the planet is not as great --- only about 200--300:1, instead of 10^6--10^10 to 1 in the optical/near-IR.
There have been some recent discoveries of some "super-Earth" planets, e.g. GJ 876d and a planet found through gravitational microlensing, that have masses several times that of Earth. In the core-accretion scenario for planet formation, it's hard to stop runaway gas accretion once it gets going, suggesting that such low-mass planets are rocky and not gaseous. Perhaps they're the remnant cores of former gas giants that have lost their gaseous envelopes via some process that occurred after formation.
Here's an older press release (with dewar pic) that has a little bit more info. Looks like lab tests were able to provide a null depth of 10^3 vs. 10^2 reported on-sky in the current blurb.
Finally, since I haven't seen a one sentence synopsis, a nulling interferometer does a careful job making the on-axis starlight received by two telescopes interfere destructively, while off-axis light from circumstellar emission passes through the system. This instrument is designed to study dust emission analogous to the zodiacal light in our own solar system.
While definitely a very useful technology, AO will not guarantee orbital telescopes obsolescence. In addition to distorting wavefronts, the atmosphere both absorbs incoming radiation and glows on its own. This means space telescopes such as HST are much more sensitive to faint objects in certain regions of the spectrum (like visible and UV light).
It would take a prohibitively long time for a ground-based telescope to acquire data for a project such as this.
Sean Mauch has a free online book covering several areas of applied mathematics. It's not complete, but I've found it useful. The page for the book is here.
Over long distances, optical laser beams will scintillate because of turbulent fluctuations in the index of refraction of the atmosphere. Relatively expensive adaptive optics systems using deformable mirrors are needed for correction.
I bet it's hard to find a professional astronomer who wouldn't produce false-color images. The reason multiple images have to be combined to get color information is that most astronomical detectors just count photons -- they don't sense color information. Astronomers doing imaging work get color info by taking exposures behind different filters and combining them with some sort of color map.
I'm sure the color table in this image was adjusted to bring out features, but real astronomers do this all the time (but they are more systematic about it...). Actually, many sources are very vibrant due to the fact that different molecules and ionization species emit at certain spectral lines. There are just huge clouds that are effectively neon lamps -- taking the energy from the supernova explosion and turning it into light at spectral lines.
Also, the "lens flares" you refer to are real. They are diffraction effects due to the support structure of the telescope. No real image of a star field would have points of light for stellar images.
Personally, I appreciate the PR efforts. Opportunities for the general public to get some sort of appreciation for science, whether it's just a pretty picture or not, is effectively raising the public awareness. Maybe the scientific value of this image is in inspiring the astronomers of the future.
Good idea... interference isn't a problem for radio dish arrays, like the VLA.
The greater the number of transmitters that are out there, you need more receiver antennae (and processing power) to distinguish which direction the desired signal is coming from.
Thus "unlimited bandwidth for everyone" doesn't seem as economical, especially if your receivers are really expensive.
I didn't notice any mention of velocity data from the article, or what method was used to determine distance. This would be important in understanding the ring's history.
However, one could speculate that if these stars are indeed part of a ring, the ring may have formed through a collision with another galaxy. For an example, check this out. Here is another example of a ring galaxy.
This is probably noteworthy because of the coolness factor. A good site and well-cooled imaging arrays are not so easy to come by at an amateur level, so if you don't want to invest heavily in hardware, you can try a few things to see if they suit your taste. I would imagine that most buyers aim at targets for "pretty pictures," instead of for some home-brewed science project.
From a strictly scientific perspective, it's probably not cost-effective to run a research project from a site like this. First of all, most astromonomical research requires some amount of spectroscopy. Of course, looking at a spectrum isn't as visually stunning (to some of us) as an awesome Hubble photo.
But, we must keep in mind that important science can be done from the ground. Ever found a supernova, asteroid, or comet? There are several unmanned, robotic telescopes around the world that are constantly searching the skies for just these types of object. This is the sort of thing that a hacker with a few bucks to spare (for equipment) could get into.
Re:SETI Concerns?
on
DOD vs. 802.11b
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· Score: 2, Interesting
I think all astronomers, not just SETI folk, are concerned about interference. Remember, these signals may not look like random noise.
Radio interference is a problem in astronomy that continues to grow. Astronomers consider the amount of interference as an important factor when choosing sites for new arrays, sometimes situating them in valleys to help mitigate these effects. Indeed, there are radio-quiet zones around major facilities, where (e.g.) cell-phone use is prohibited.
I'm sure some astronomers would be smirking at the military now getting concerned about interference problems (when the military generally didn't care about their systems interfering with astronomy), if it were not for the fact that these problems affect us all.
I think showers seem to be surfacing more in consciousness because of the Leonids. It's been observed that every 33 years or so, they pick up in activity. This because the Earth passes through/near the parent comet's orbit soon after the comet passes near Earth's orbit, so there's probably a higher density of ice and rock chunks. The activity was supposed to peak in '99 - '00 as it did in '66.
I've enjoyed the Geminids more than the Leonids, though, so go out to some dark skies and watch!
Sure, finding a signal from ET is a longshot. But the project is also useful for real science in astrophysics.
The large computational power available is unique and makes it extremely useful for finding many kinds of time-variable radio sources (not just ET). The project is also being used to map the Hydrogen in the galaxy as detailed here.
Even though getting signals from an extraterrestrial intelligence may be a pipe dream, the project still has value from a pure scientific standpoint.
Slashdot Mirror
These data were taken in the mid-infrared, where the contrast between the star and the planet is not as great --- only about 200--300:1, instead of 10^6--10^10 to 1 in the optical/near-IR.
There have been some recent discoveries of some "super-Earth" planets, e.g. GJ 876d and a planet found through gravitational microlensing, that have masses several times that of Earth. In the core-accretion scenario for planet formation, it's hard to stop runaway gas accretion once it gets going, suggesting that such low-mass planets are rocky and not gaseous. Perhaps they're the remnant cores of former gas giants that have lost their gaseous envelopes via some process that occurred after formation.
Finally, since I haven't seen a one sentence synopsis, a nulling interferometer does a careful job making the on-axis starlight received by two telescopes interfere destructively, while off-axis light from circumstellar emission passes through the system. This instrument is designed to study dust emission analogous to the zodiacal light in our own solar system.
It would take a prohibitively long time for a ground-based telescope to acquire data for a project such as this.
Sean Mauch has a free online book covering several areas of applied mathematics. It's not complete, but I've found it useful. The page for the book is here.
Over long distances, optical laser beams will scintillate because of turbulent fluctuations in the index of refraction of the atmosphere. Relatively expensive adaptive optics systems using deformable mirrors are needed for correction.
I bet it's hard to find a professional astronomer who wouldn't produce false-color images. The reason multiple images have to be combined to get color information is that most astronomical detectors just count photons -- they don't sense color information. Astronomers doing imaging work get color info by taking exposures behind different filters and combining them with some sort of color map.
I'm sure the color table in this image was adjusted to bring out features, but real astronomers do this all the time (but they are more systematic about it...). Actually, many sources are very vibrant due to the fact that different molecules and ionization species emit at certain spectral lines. There are just huge clouds that are effectively neon lamps -- taking the energy from the supernova explosion and turning it into light at spectral lines.
Also, the "lens flares" you refer to are real. They are diffraction effects due to the support structure of the telescope. No real image of a star field would have points of light for stellar images.
Personally, I appreciate the PR efforts. Opportunities for the general public to get some sort of appreciation for science, whether it's just a pretty picture or not, is effectively raising the public awareness. Maybe the scientific value of this image is in inspiring the astronomers of the future.
Today's APOD has a pic of Jupiter in IR (can't see the pole though).
The greater the number of transmitters that are out there, you need more receiver antennae (and processing power) to distinguish which direction the desired signal is coming from.
Thus "unlimited bandwidth for everyone" doesn't seem as economical, especially if your receivers are really expensive.
I didn't notice any mention of velocity data from the article, or what method was used to determine distance. This would be important in understanding the ring's history.
However, one could speculate that if these stars are indeed part of a ring, the ring may have formed through a collision with another galaxy. For an example, check this out. Here is another example of a ring galaxy.
This is probably noteworthy because of the coolness factor. A good site and well-cooled imaging arrays are not so easy to come by at an amateur level, so if you don't want to invest heavily in hardware, you can try a few things to see if they suit your taste. I would imagine that most buyers aim at targets for "pretty pictures," instead of for some home-brewed science project.
From a strictly scientific perspective, it's probably not cost-effective to run a research project from a site like this. First of all, most astromonomical research requires some amount of spectroscopy. Of course, looking at a spectrum isn't as visually stunning (to some of us) as an awesome Hubble photo.
But, we must keep in mind that important science can be done from the ground. Ever found a supernova, asteroid, or comet? There are several unmanned, robotic telescopes around the world that are constantly searching the skies for just these types of object. This is the sort of thing that a hacker with a few bucks to spare (for equipment) could get into.
I think all astronomers, not just SETI folk, are concerned about interference. Remember, these signals may not look like random noise.
Radio interference is a problem in astronomy that continues to grow. Astronomers consider the amount of interference as an important factor when choosing sites for new arrays, sometimes situating them in valleys to help mitigate these effects. Indeed, there are radio-quiet zones around major facilities, where (e.g.) cell-phone use is prohibited.
I'm sure some astronomers would be smirking at the military now getting concerned about interference problems (when the military generally didn't care about their systems interfering with astronomy), if it were not for the fact that these problems affect us all.
I think showers seem to be surfacing more in consciousness because of the Leonids. It's been observed that every 33 years or so, they pick up in activity. This because the Earth passes through/near the parent comet's orbit soon after the comet passes near Earth's orbit, so there's probably a higher density of ice and rock chunks. The activity was supposed to peak in '99 - '00 as it did in '66.
I've enjoyed the Geminids more than the Leonids, though, so go out to some dark skies and watch!
Sure, finding a signal from ET is a longshot. But the project is also useful for real science in astrophysics.
The large computational power available is unique and makes it extremely useful for finding many kinds of time-variable radio sources (not just ET). The project is also being used to map the Hydrogen in the galaxy as detailed here.
Even though getting signals from an extraterrestrial intelligence may be a pipe dream, the project still has value from a pure scientific standpoint.