Just to correct some misconceptions in that
funny pressure-cooked comment:
high density==pressure: the density of a planet is completely unrelated to the atmospheric pressure Venus is slightly less dense than Earth, but its atmospheric pressure is 90 times higher. Even the Suturn moon Titan has a higher atmospheric pressure (1.6 Bar) than Earth. And it is the atmospheric pressure
that determines the range of temperatures where
water is liquid.
small size==low gravitational mass: Earth has the third largest surface gravity of all planets in the solar system
(in case you wonder, the 'surface' of a gas giant
is defined by its radius, which is the level where
the atmospheric pressure is one Bar). And it is the surface gravity that determines the (mechanical) stresses on an animal or plant.
Proximity to Sun==dynamic energy ('chaos'):
From which cult/religion is that taken ?
If such moons were similar to the moons of Jupiter or Saturn, their gravity would be way too low to keep an atmosphere and have liquid surface water (you need an atmosphere, because liquid water will evaporate at sufficiently low pressure).
The big difference in our solar system is that the gas giants are far from the sun, hence their moons are cold, which allows the Saturn moon Titan to keep a (mostly nitrogen) atmosphere. With higher temperatures, the gas molecules move faster, and
the escape velocity is reached more easily, thus
a larger gravity is required.
There was a paper by Darren Williams and two other authors in Nature back in 1997 which discussed the requirements for habitable moons. You can find a summary here. Basically it says that
to keep an atmosphere, you need at least 0.12 the mass of Earth (i.e. five times the mass of the largest moon in the solar system, the Jupiter moon Ganymede).
Moreover, the authors argue that the moon must be
able to remain
geologically active for several billion years (to resupply carbon dioxide), which pushes the minimum mass up to 0.23 the mass of Earth. That would be twice the mass of Mars.
The article fails to mention that the quoted masses are just lower limits, because the inclination of the planet orbits to our line of sight is unknown. One would need to divide by the
sine of the inclination to obtain the true mass of the planet (as the inclination can range between
0 and 90 deg, its sine is between 0 and 1).
While very large masses can be excluded by other arguments (the planet would be more luminous than the parent star), there is still a fairly large range for the planet mass.
You need energy to brake a spinning disk, not to keep it spinning. If you can reduce
the friction to zero (think of magnetic bearings
with room-temperature superconduction magnets in
an evacuated case), the hard drive will spin forever.
Of course there are no room-temperature superconducting materials known yet (and strong magnetic fields may cause problems..), but the point is that current devices are far from the limits
set by the laws of physics.
Also, if you use a head-worn display instead of
a huge screen, the size and power output of the LCD drops substantially.
It's good to see an article that cares about usability instead of the usual speed comparison (which is completely irrelevant to the average user that just wants to type her letter).
E.g. humans tend to sort things mentally by "access time" rather than by a hierachical directory structure, which makes features like a "last used program" option a great thing.
It would be interesting to extend this to a file manager that does a mathematical cluster analysis based on access time, and puts files from different directories but with similar access times into common "heaps" (which is exactly the way many people order papers, books, etc on their desk).
Another problem is that many "Joe Users" never use
the (m$ windows) help system, because it is not well structured (just get some Joe Users and ask them - chances are you will hear something along "I cannot find any useful help there"). I don't think that the Gnome/KDE help systems are much better.
The way Linux vendors modify the desktop menues does not help either. E.g. SuSE puts in a "SuSE" menue into the KDE menue. It is quite confusing that some apps might be found under "Applications" but others under "Suse".
Rather than waiting for the next cool feature from
M$, and copy it, it would be interesting to get hold of a few "Joe Users", and ask them what they like/dislike most in existing interfaces (e.g.: menues are good - submenues are bad - subsubmenues are plain evil - based on performing this experiment).
The duration of the event was about 3 hours, i.e. about 10000 sec, and the article says that is was "500-1000 times more energetic" than a normal event, which is something like 10 sec long.
Thus, the power (energy/sec, in whatever units) apparently was similar to a normal event, and only the length of this event was different.
BTW, the article doesn't mention that any mass was ejected from the neutron star (all what is measured is X-ray emission). If thermonuclear burning on the neutron star has occured for a few hours, the burning layer most likely was in some temporarily stable state, which does not favour the idea of mass ejection.
Neutron stars are the remnants of supernova explosions. It is well known by now that the neutron star often speeds away from the explosion with a "kick velocity" of several 100 km/s (as far as I know, the record is well above 1000 km/s). The reason is not yet clear, although there are some theories, one of them being asymmetric explosion. More theories can be found
here.
So the speed of RX J1856.5-3754 (about 85-100 km/s) is more in the lower range. What make this star interesting is not its velocity, but the fact that it is rather unique, because it does not show any activity (e.g. pulsations), unlike most other known neutron stars.
Also, as there is no gaseous shell from the supernova left, thus it must be quite old (at least 100000 yrs), but nevertheless the neutron star is still rather hot (as evidenced by its X-ray emission). This is puzzling because neutron stars have no internal energy source (unlike "normal" stars that are powered by thermonuclear reactions), and therefore should cool down continuously from the moment of birth.
There is an ESO Press Release about this object which offers much more info than the CNN article, yet is still written for
non-scientists.
If you're running on Windows, you're probably using IE.
I am using IE when running on Windows, and I definitely don't like it. It may start up faster, but the user interface is crap, compared to Netscape
(and I am too lazy to install Netscape on an OS that I use just a few minutes per day).
The article is rather confusingly written, because taken at face value, it is not clear at all what has been shown by this study.
It says that the investigated galaxies were
Seyfert galaxies, i.e. galaxies that presumably harbour a massive black hole. Furthermore, it says:
(a) "Previous research had identified the galaxies they studied as having some characteristics of
starburst galaxies.", and
(b) "Starburst galaxies in the new study also were near to or interacting with other galaxies"
This would imply that the investigated galaxies
were not a random sample of Seyfert galaxies, but selected on the fact that they also show star formation.
Obviously the theory that both are related
could only be proven with a random sample (i.e. take N Seyfert galaxies and prove that most/all of
them show violent star formation, or vice versa).
One of the rarely mentioned problems of the GPL is that it is developed for the US law, but used by an international community.
To my knowledge, there has been no lawsuit yet in Germany, but there is a group of lawyers who have analyzed the GPL (ifross). Unfortunately, their publications
are in German only.
One of their conclusions is that the "any later version" clause might not be valid under German law.
From reading the argument, the implication seems to be that (in Germany) you could not legally redistribute GPL2 code with a GPL3 license if the GPL3 license would allow additional modes of usage. On the other hand apparently you cannot use GPL2 code for ASP in Germany if it was written before ASP was widely known...
BTW, the "no warranty" clause is also not valid in Germany.
Slashdot Mirror
high density==pressure: the density of a planet is completely unrelated to the atmospheric pressure Venus is slightly less dense than Earth, but its atmospheric pressure is 90 times higher. Even the Suturn moon Titan has a higher atmospheric pressure (1.6 Bar) than Earth. And it is the atmospheric pressure that determines the range of temperatures where water is liquid.
small size==low gravitational mass: Earth has the third largest surface gravity of all planets in the solar system (in case you wonder, the 'surface' of a gas giant is defined by its radius, which is the level where the atmospheric pressure is one Bar). And it is the surface gravity that determines the (mechanical) stresses on an animal or plant.
Proximity to Sun==dynamic energy ('chaos'): From which cult/religion is that taken ?
The big difference in our solar system is that the gas giants are far from the sun, hence their moons are cold, which allows the Saturn moon Titan to keep a (mostly nitrogen) atmosphere. With higher temperatures, the gas molecules move faster, and the escape velocity is reached more easily, thus a larger gravity is required.
There was a paper by Darren Williams and two other authors in Nature back in 1997 which discussed the requirements for habitable moons. You can find a summary here. Basically it says that to keep an atmosphere, you need at least 0.12 the mass of Earth (i.e. five times the mass of the largest moon in the solar system, the Jupiter moon Ganymede).
Moreover, the authors argue that the moon must be able to remain geologically active for several billion years (to resupply carbon dioxide), which pushes the minimum mass up to 0.23 the mass of Earth. That would be twice the mass of Mars.
While very large masses can be excluded by other arguments (the planet would be more luminous than the parent star), there is still a fairly large range for the planet mass.
You need energy to brake a spinning disk, not to keep it spinning. If you can reduce the friction to zero (think of magnetic bearings with room-temperature superconduction magnets in an evacuated case), the hard drive will spin forever. ..), but the point is that current devices are far from the limits
set by the laws of physics.
Of course there are no room-temperature superconducting materials known yet (and strong magnetic fields may cause problems
Also, if you use a head-worn display instead of a huge screen, the size and power output of the LCD drops substantially.
Another problem is that many "Joe Users" never use the (m$ windows) help system, because it is not well structured (just get some Joe Users and ask them - chances are you will hear something along "I cannot find any useful help there"). I don't think that the Gnome/KDE help systems are much better.
The way Linux vendors modify the desktop menues does not help either. E.g. SuSE puts in a "SuSE" menue into the KDE menue. It is quite confusing that some apps might be found under "Applications" but others under "Suse".
Rather than waiting for the next cool feature from M$, and copy it, it would be interesting to get hold of a few "Joe Users", and ask them what they like/dislike most in existing interfaces (e.g.: menues are good - submenues are bad - subsubmenues are plain evil - based on performing this experiment).
BTW, the article doesn't mention that any mass was ejected from the neutron star (all what is measured is X-ray emission). If thermonuclear burning on the neutron star has occured for a few hours, the burning layer most likely was in some temporarily stable state, which does not favour the idea of mass ejection.
So the speed of RX J1856.5-3754 (about 85-100 km/s) is more in the lower range. What make this star interesting is not its velocity, but the fact that it is rather unique, because it does not show any activity (e.g. pulsations), unlike most other known neutron stars.
Also, as there is no gaseous shell from the supernova left, thus it must be quite old (at least 100000 yrs), but nevertheless the neutron star is still rather hot (as evidenced by its X-ray emission). This is puzzling because neutron stars have no internal energy source (unlike "normal" stars that are powered by thermonuclear reactions), and therefore should cool down continuously from the moment of birth.
There is an ESO Press Release about this object which offers much more info than the CNN article, yet is still written for non-scientists.
I am using IE when running on Windows, and I definitely don't like it. It may start up faster, but the user interface is crap, compared to Netscape (and I am too lazy to install Netscape on an OS that I use just a few minutes per day).
It says that the investigated galaxies were Seyfert galaxies, i.e. galaxies that presumably harbour a massive black hole. Furthermore, it says:
(a) "Previous research had identified the galaxies they studied as having some characteristics of starburst galaxies.", and
(b) "Starburst galaxies in the new study also were near to or interacting with other galaxies"
This would imply that the investigated galaxies were not a random sample of Seyfert galaxies, but selected on the fact that they also show star formation.
Obviously the theory that both are related could only be proven with a random sample (i.e. take N Seyfert galaxies and prove that most/all of them show violent star formation, or vice versa).
From reading the argument, the implication seems to be that (in Germany) you could not legally redistribute GPL2 code with a GPL3 license if the GPL3 license would allow additional modes of usage. On the other hand apparently you cannot use GPL2 code for ASP in Germany if it was written before ASP was widely known...
BTW, the "no warranty" clause is also not valid in Germany.