The initial gas mix of stars is approximately 95% Hydrogen (H) and about 5% Helium (He), with a very tiny fraction of Lithium and heavier elements. Anything heavier than Helium is considered a "metal" to an astronomer, BTW.
Stars produce the most energy by fusing H into He, and they can also gain some energy by fusing heavier elements, but the amount of energy declines until you reach Iron (Fe), after which fusion no longer results in an energy gain. Once a star starts having a lot of Fe in its core, the fusion synthesis process stops producing the energy needed to keep the star going, so it collapses, and the rebound shock causes a nova, also producing elements heavier than Iron as a result.
The approximate distribution of elements in Sol, our sun, today is:
Planets like Earth have a much higher distribution of heavier elements than stars do, for a very simple reason: they aren't big enough to have enough gravity to keep things like H and He from escaping over time, unless the planet is above a critical mass, in which case it forms a gas giant like Jupiter, Saturn, etc, which are big enough to retain such very light gasses.
Here's a table of the planets in our solar system, with mass measured in 10**24 kg, density relative to water, then the heaviest molecular weight of a gas the planet will retain, and the lightest common atmospheric gas which is kept:
In particular, oxygen gas, O2, has a molecular weight of 32, and N2 is 28. If Mars were just a little bit heavier, it would have a much more substantial atmosphere which would be much more similar to that here on Earth.
-Chuck
PS: Why yes, that's a Python dictionary above, you didn't think I'd write the table above by hand or post using "Code" frivolously, do you...? :-)
Did Steve Jobs run over your pet, or is there a reason you're flaming Apple for their position with open source?
I mean, if you want to criticise Apple, by all means, there are plenty of legitimate reasons to do so...but claiming that Microsoft is "following the true spirit of open source" more than Apple is obviously nonsense.
If you want to deal with some facts, try asking the Apache folks whether Apple has been contributing changes and bugfixes back to apache.org in return for shipping the Apache webserver with OS X. Or talk to Larry Wall and the Perl folks. Or talk to the gcc folks about the compiler changes in gcc-4.0 which Apple worked on to improve PPC (in specific)/64-bit (in general) codegen.
And before I get typecast as an Apple fanboy, let me point out that Sun has done at least as much as Apple in terms of working with open source projects, as well as making huge contributions before the notion of "Open Source" even existed.
Never mind OpenSolaris 10, for all that FreeBSD and other projects are interested in Sun's kernel microbenchmarks and the dtrace kernel/process tracing capabilities to improve upon truss and ktrace, you can go all the way back to RPC, XDR, NFS, NIS, and other common Unix capabilities which Sun shared with the world via open standards and the RFC process, many years (or even a decade or so) before Linux or even the GPL itself was written.
Hey, I can criticise Sun too: see the Java license. But Java itself was a lot more open until Microsoft started playing the enhance, break compatibility game-- Sun had clear provocation and reason for making Java more restrictive, even if I disagree with the approach they took.
The version you're talking about is what the bsd-family-tree document calls "4.3BSD NET/1", which is between "4.3BSD Tahoe" and "4.3BSD Reno".
The earliest version of BSD software under an open source license dates back to approximately 1977, although only small parts of the total Unix system were under that license, most of it was under the AT&T license (BSD started forking from the "Sixth Edition (V6)").
If you want to talk about the first complete operating system release which was not encumbered by the AT&T/USL/SCO license, you'd have to look to "4.4BSD Lite" circa 1993?, from which FreeBSD 2.0, NetBSD 1.0, and BSD/OS 2.0 were derived. OpenBSD and Rhapsody/MacOS X then followed up from a second release of the un-encumbered BSD sources (called "4.4BSD Lite2").
Consult the file/usr/share/misc/bsd-family-tree, or Google for it if you don't happen to be running a BSD Unix.
zlib is open source. The zlib license is closely related to the classic BSD-style license, and was one of the earlier licenses approved by the Open Source Initiative, which lists the zlib license here:
zlib is simply released with no strings attached whatsoever. only catch is that the author's not responsible for anything that happens with it.
This is roughly correct; the Zlib license is a simple permissive license.
most people equate OSS with the GPL or a BSD-style license.
Most people should equate "Open Source Software" with "being compliant with the Open Source Definition (OSD)", see link above.
This being said, the OSD itself is derived from some people at Debian Linux who came up with the "Debian Free Software Guidelines", to help their project figure out which licenses were compatible with their goals. The first four licenses considered as such were the GPL, LGPL, BSD, and MIT/X11 licenses.
zlib is released more or less without any license at all. It's a few lines that make it VERY VERY CLEAR that the authors don't care what the hell you do with it as long as they're not implicated
This is quite wrong: zlib is released under a simple, clear, permissive license.
That is not the same thing as "without any license at all".
A good fluoresent bulb shouldn't flicker, but older ones sure did, and yeah, they give lotsa people headaches.
The thing is, the older bulbs tended to just have one phosphor (ie, would be either a reddish tint, or a pale blueish tint), and you were supposed to mix and match tubes to have some of both lighting the area to sort of blend into a neutral white.
Those sort of bulbs look like crap, IMO, but newer tubes combine both phosphors and produce something closer to a normal white light, which is easier on the eyes and a lot less annoying.
All of this being said, I'd rather use halogen, except for the heat. This being summer and all, a ~20W fluorescent bulb beats the heck out of a 100W incandescent, or a 300W halogen in terms of not heating the room up....
Gosh, putting a game on a bootable disk is pretty much what console games do.
Of course, you only need to deal with a very specific, known set of hardware, rather than the wide world of x86 hardware, which makes setting up a turnkey system much easier. For example, if your game on a bootable CD doesn't have drivers for the latest video card you just got, and the software can't be updated because the OS is burned onto the CD/DVD, what freaken good is that?
Most games nowadays want to save stuff somewhere, which means they need to share a harddrive (or memory card, etc) and coordinate who puts stuff where. And that's why you use an OS, to coordinate resources, manage the hardware and let the game programmers concentrate on their stuff, writing a cool game....
mod parent up, but don't be paranoid about florescent bulbs, either. The amount of mercury in a normal 4-foot tube is about 5mg, which is about the same volume as the amount of ink on the tip of a ball-point pen.
Sure you don't want to break a bulb and inhale the vapors deliberately, sure Hg is toxic, but if you break a bulb, it's not going to kill everyone within 100 feet, either. There isn't enough Hg in one bulb to be that dangerous. Good link here:
"Safe cleanup precautions: If a CFL breaks in your home, open nearby windows to disperse any vapor that may escape, carefully sweep up the fragments (do not use your hands) and wipe the area with a disposable paper towel to remove all glass fragments. Do not use a vacuum. Place all fragments in a sealed plastic bag and follow disposal instructions above."
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The initial gas mix of stars is approximately 95% Hydrogen (H) and about 5% Helium (He), with a very tiny fraction of Lithium and heavier elements. Anything heavier than Helium is considered a "metal" to an astronomer, BTW.
Stars produce the most energy by fusing H into He, and they can also gain some energy by fusing heavier elements, but the amount of energy declines until you reach Iron (Fe), after which fusion no longer results in an energy gain. Once a star starts having a lot of Fe in its core, the fusion synthesis process stops producing the energy needed to keep the star going, so it collapses, and the rebound shock causes a nova, also producing elements heavier than Iron as a result.
The approximate distribution of elements in Sol, our sun, today is:
{'H':.785, 'He':.197, 'O':.0097, 'C':.004, 'N':.001, 'Si':.001, 'Mg':.00076, 'Ne':.00058, 'Fe':.00014, 'S':.0004}
Planets like Earth have a much higher distribution of heavier elements than stars do, for a very simple reason: they aren't big enough to have enough gravity to keep things like H and He from escaping over time, unless the planet is above a critical mass, in which case it forms a gas giant like Jupiter, Saturn, etc, which are big enough to retain such very light gasses.
Here's a table of the planets in our solar system, with mass measured in 10**24 kg, density relative to water, then the heaviest molecular weight of a gas the planet will retain, and the lightest common atmospheric gas which is kept:
Mercury mass: 0.33 density: 5.43 moleculelim: 43.5 gas: CarbonDioxide
Venus mass: 4.87 density: 5.24 moleculelim: 7.3 gas: Methane
Earth mass: 5.97 density: 5.51 moleculelim: 6.3 gas: Methane
Mars mass: 0.64 density: 3.93 moleculelim: 31.1 gas: OxygenGas
Jupiter mass: 1899.00 density: 1.33 moleculelim: 0.2 gas: HydrogenGas
Saturn mass: 568.00 density: 0.69 moleculelim: 0.6 gas: HydrogenGas
Uranus mass: 86.80 density: 1.27 moleculelim: 1.7 gas: HydrogenGas
Neptune mass: 102.00 density: 1.64 moleculelim: 1.4 gas: HydrogenGas
Pluto mass: 0.01 density: 1.75 moleculelim: 578.5 gas: None
In particular, oxygen gas, O2, has a molecular weight of 32, and N2 is 28. If Mars were just a little bit heavier, it would have a much more substantial atmosphere which would be much more similar to that here on Earth.
-Chuck
PS: Why yes, that's a Python dictionary above, you didn't think I'd write the table above by hand or post using "Code" frivolously, do you...? :-)
Did Steve Jobs run over your pet, or is there a reason you're flaming Apple for their position with open source?
I mean, if you want to criticise Apple, by all means, there are plenty of legitimate reasons to do so...but claiming that Microsoft is "following the true spirit of open source" more than Apple is obviously nonsense.
If you want to deal with some facts, try asking the Apache folks whether Apple has been contributing changes and bugfixes back to apache.org in return for shipping the Apache webserver with OS X. Or talk to Larry Wall and the Perl folks. Or talk to the gcc folks about the compiler changes in gcc-4.0 which Apple worked on to improve PPC (in specific)/64-bit (in general) codegen.
And before I get typecast as an Apple fanboy, let me point out that Sun has done at least as much as Apple in terms of working with open source projects, as well as making huge contributions before the notion of "Open Source" even existed.
Never mind OpenSolaris 10, for all that FreeBSD and other projects are interested in Sun's kernel microbenchmarks and the dtrace kernel/process tracing capabilities to improve upon truss and ktrace, you can go all the way back to RPC, XDR, NFS, NIS, and other common Unix capabilities which Sun shared with the world via open standards and the RFC process, many years (or even a decade or so) before Linux or even the GPL itself was written.
Hey, I can criticise Sun too: see the Java license. But Java itself was a lot more open until Microsoft started playing the enhance, break compatibility game-- Sun had clear provocation and reason for making Java more restrictive, even if I disagree with the approach they took.
The version you're talking about is what the bsd-family-tree document calls "4.3BSD NET/1", which is between "4.3BSD Tahoe" and "4.3BSD Reno".
/usr/share/misc/bsd-family-tree, or Google for it if you don't happen to be running a BSD Unix.
The earliest version of BSD software under an open source license dates back to approximately 1977, although only small parts of the total Unix system were under that license, most of it was under the AT&T license (BSD started forking from the "Sixth Edition (V6)").
If you want to talk about the first complete operating system release which was not encumbered by the AT&T/USL/SCO license, you'd have to look to "4.4BSD Lite" circa 1993?, from which FreeBSD 2.0, NetBSD 1.0, and BSD/OS 2.0 were derived. OpenBSD and Rhapsody/MacOS X then followed up from a second release of the un-encumbered BSD sources (called "4.4BSD Lite2").
Consult the file
zlib is open source. The zlib license is closely related to the classic BSD-style license, and was one of the earlier licenses approved by the Open Source Initiative, which lists the zlib license here:
http://www.opensource.org/licenses/zlib-license.ph p
The Zlib license is also "free" according to the FSF, and is GPL-compatible:
http://www.fsf.org/licensing/licenses/index_html#G PLCompatibleLicenses
This is roughly correct; the Zlib license is a simple permissive license. Most people should equate "Open Source Software" with "being compliant with the Open Source Definition (OSD)", see link above.This being said, the OSD itself is derived from some people at Debian Linux who came up with the "Debian Free Software Guidelines", to help their project figure out which licenses were compatible with their goals. The first four licenses considered as such were the GPL, LGPL, BSD, and MIT/X11 licenses.
This is quite wrong: zlib is released under a simple, clear, permissive license.That is not the same thing as "without any license at all".
-Chuck
The browser you've mentioned is known as a "Miller-column browser", and I think it was inherited from Smalltalk by NEXTSTEP.
http://en.wikipedia.org/wiki/Fluorescent_tube
A good fluoresent bulb shouldn't flicker, but older ones sure did, and yeah, they give lotsa people headaches.
The thing is, the older bulbs tended to just have one phosphor (ie, would be either a reddish tint, or a pale blueish tint), and you were supposed to mix and match tubes to have some of both lighting the area to sort of blend into a neutral white.
Those sort of bulbs look like crap, IMO, but newer tubes combine both phosphors and produce something closer to a normal white light, which is easier on the eyes and a lot less annoying.
All of this being said, I'd rather use halogen, except for the heat. This being summer and all, a ~20W fluorescent bulb beats the heck out of a 100W incandescent, or a 300W halogen in terms of not heating the room up....
Gosh, putting a game on a bootable disk is pretty much what console games do.
Of course, you only need to deal with a very specific, known set of hardware, rather than the wide world of x86 hardware, which makes setting up a turnkey system much easier. For example, if your game on a bootable CD doesn't have drivers for the latest video card you just got, and the software can't be updated because the OS is burned onto the CD/DVD, what freaken good is that?
Most games nowadays want to save stuff somewhere, which means they need to share a harddrive (or memory card, etc) and coordinate who puts stuff where. And that's why you use an OS, to coordinate resources, manage the hardware and let the game programmers concentrate on their stuff, writing a cool game....
mod parent up, but don't be paranoid about florescent bulbs, either. The amount of mercury in a normal 4-foot tube is about 5mg, which is about the same volume as the amount of ink on the tip of a ball-point pen.
p df
Sure you don't want to break a bulb and inhale the vapors deliberately, sure Hg is toxic, but if you break a bulb, it's not going to kill everyone within 100 feet, either. There isn't enough Hg in one bulb to be that dangerous. Good link here:
http://www.nema.org/lamprecycle/epafactsheet-cfl.
"Safe cleanup precautions: If a CFL breaks in your home, open nearby windows to disperse any vapor that may escape, carefully sweep up the fragments (do not use your hands) and wipe the area with a disposable paper towel to remove all glass fragments. Do not use a vacuum. Place all fragments in a sealed plastic bag and follow disposal instructions above."