The home page of Armadillo Aerospace
says that the rocket is hydrogen peroxide
fueled. But hydrogen peroxide (H_2 O_2) is
just the oxidizer, right? What is the fuel,
I wonder? The rocket produces almost no visible
flames
.
several months ago I posted a question regarding
dark energy
Speaking of dark energy, I wonder whether [suppose it exists indeed] dark energy does not break the law of conservation of energy. Once I attended a public talk by someont from Fermi Lab [sorry, cannot recall the name] who said that dark energy is a constant quantity [a very small number in standard units] per volume of space. So, given that the Universe is expanding and is being pushed more and more this way by the dark energy, the quantity of dark energy goes up and up, right? So, if it has indeed the meaning of energy, there is more and more energy in the Universe, contrary to the law of conservation...
Sadly, after the mention public talk only very few questions were allowed and I missed the opportunity to ask the expert in person.
It got moddep up as Interesting +1, but nobody
answered. Maybe this time...
I don't have a quicktime plug-in, but even
if I had, my Internet connection is ridiculous, so...
Does anyone know a URL for the trailer? I mean,
for download of the movie. Thanks.
For some reason, acroread 5.* segfaults of RedHat 9.0.
And acroread 4.* is not good for this texbook as
they warn. But xpdf works fine -- that's how I read
it now.
Normally, "supersonic" means moving faster
than the speed of sound in the respective
environment. And "hyper" normally is used
as a stronger form of "super"[1]. E.g.,
supermarket <-> hypermarket, and so on.
To me, hypersonic means moving much, much
faster than the speed of sound. Which is not
the intended meaning here -- they are talking
about soundwaves, so how can the soundwaves
move faster than sound?
[1] - AFAIK, in Greek hyper means the same
as super in Latin, namely above.
Yes, that is what I meant, thank you.
Obviously, hitting something (the Earth,
the Moon, a stray asteroid, GPS satellite,
etc.) would be the end of the journey,
but that is not the point.
Escape velocity is necessary only when you
want to, well, escape the Earth:)). If you
want to go into Earth's orbit, the velocity
is 7.8km/s. In fact, this is the minimum
velocity you need, given that the direction
of the movement is perpendicular to the
line that connects you with the center of the Earth, never to fall down.
AFAIR, 7.8km/s is that velocity at the Earth's
surface. Since there is air friction at the surface, it makes sense to consider that velocity
at, say, 250km or more above the surface -- it
is surely smaller there, of course, and grows
smaller as you go up, because the Earth's
gravitational pull grows weaker.
When I studied these things in secondary school,
we called 7.8km/s, "first space velocity", and
11.2km/s, "second space velocity". I think the
terms are Russian (pervaya kosmicheskaya skorosty,
vtoraya kosmicheskaya skorosty).
So an escape velocity can vary in speed as the angle of escape changes.
Wrong! It absolutely does not matter which
direction the velocity vector points to.
All that matters is the kinetik energy of
the body. The kinetic energy is 1/2 * m * (v^2),
where v is scalar, the speed in your terminology.
See this
page
, it is really neat, you can compute
escape velocities for different planets.
I already posted this in another discussion
here, but probably it is worth mentioning
again. The bigger cousin of X-43A, X-43C, is
being
cancelled
because it does not fit in the new space plans.
ROM. Stick RAM at the beginning of the address space and ROM at the end of the address space and you can add maximum amounts of both without them colliding.
Thanks. So, the mechanism for addressing (however it is properly called) which is part of the chipset (right?) knows that when the address is
at the very top/bottom, it has to turn to the ROM chip, not the SDRAM. What about during normal operation of the OS, are the very top/bottom still mapped to ROM?
So, what's at address 0xfffffff0 when there
are only, say, 512MB installed? I realise that
when the OS is running, the virtual addresses
are translated into physical ones, but presumably
at boot time the VM mechanism is still not
operational an this 0xfffffff0 should refer
to a true physical address. So... ?
When the PC is turned on or reset, the CPUs start fetching from a known address, which traditionally has been from the top of memory (TOM) minus 16 bytes. In the original 8086, this was address 0xffff0; on newer PCs, it is address 0xfffffff0.
0xffff0 is 1MB - 16B, the original PC's had 1MB,
so this part is clear. But 0xfffffff0 is 4GB - 16B.
How many PCs have 4GB?
By simply studying the source of a Tex/Latex
document, you can learn. I mean, if
it is done by a master in typesetting, you
can learn a lot by just studying the source.
This is not the case with the WYSIWYG approach
where you can see the end result, but you
don't know how it was obtained.
This is a bit like programming -- you can
write code that is a load of "ugly hacks", or
you can write sane, maintainable, clear code.
Even if both do the same, the second
approach is preferable for obvious reasons.
Likewise, in typesetting you can achieve the
same visual result with ugly hacks, or
with a higher-level approach where you specify
intentions and let the tool render them;
in the ugly-hacks approach too many things are hard-coded and maintenance/expanding of the
code is a nightmare (novices
inevitably do that).
My point is that one can
improve a lot more by studying the works of
the experts as source, rather than as end result.
No OpenType support. That means its utterly useless for the 75% of the world that doesn't use the American English alphabet.
?? Can you elaborate? One can typeset documents
in Bulgarian in Latex, for instance, and they look as good as they can be. Sure, there is some pain
in making it work with character coding cp1251,
sure, it does not support Unicode,
but the implication you quote above is simply
nonsense. I can find examples for you, if you
don't believe me, that it is possible to create
a Cyrillic document which looks great.
2. No support for generation of press-ready PDF's. That is to say, no PDF/X support at all.
I don't know what you mean, this concept is unfamiliar, but I do assure you there are
excellent books typeset in Latex. Introduction
to Algorithms by Cormen, Leiserson and Rivest,
or Modern Computer Algebra by J. von zur Gathen
and J. Gerhard. By "excellent" I mean they look
remarkably well, not that the content is great
(it is, but that is a different story).
Tex / Latex is intended as a tool for serious,
black-and-white, scientific writing with lots
of formulas. It may suck at colour separation,
but its math typesettings capabilities are
fantastic. The Word's equation editor is a joke
in comparison. I tried FrameMaker at one moment
and gave up. For instance, putting indices was too annoying in FM,
I had to chase some menu items with the mouse,
while in Latex I can achieve that by, say, $a_i$.
Unfortunately, it is stagnant. Or almost stagnant.
Have a look at this thread in
comp.text.tex
I agree Letex's typesetting quality is superb and it is
the standard in math / comp sci / physics publishing, but it has to develop. I find it amazing that, given its large user base at
universities and research centers, there is not
enough funding to let several of the core developers devote their energy and time to Latex.
See the thread above, F. Mittelbach (yes, that Mittelbach, the author of The Latex
Companion) says that Latex 3 has been delayed
for years and years, because the core developers
are busy with their regular jobs.
What shall I do to protect a RH9 system?
Are the rpm updates here what I need? If so, I assume I need
this
and
this -- since they are from 17.March.2004? (the *devel* package is available for i386 only, so that's why it's i386, no i686).
Slashdot Mirror
The home page of Armadillo Aerospace says that the rocket is hydrogen peroxide fueled. But hydrogen peroxide (H_2 O_2) is just the oxidizer, right? What is the fuel, I wonder? The rocket produces almost no visible flames .
What do you mean?
thanks!
Are you sure these are photos from the lates flight? Check out the directory where the jpeg's are . The files are from 19.April.2004.
I don't have a quicktime plug-in, but even if I had, my Internet connection is ridiculous, so ...
Does anyone know a URL for the trailer? I mean,
for download of the movie. Thanks.
For some reason, acroread 5.* segfaults of RedHat 9.0. And acroread 4.* is not good for this texbook as they warn. But xpdf works fine -- that's how I read it now.
Further, the client can change (aspects of) the flick to his taste :)
To me, hypersonic means moving much, much faster than the speed of sound. Which is not the intended meaning here -- they are talking about soundwaves, so how can the soundwaves move faster than sound?
[1] - AFAIK, in Greek hyper means the same as super in Latin, namely above.
but why were the super-precise quartz balls made in Germany ?
Yes, that is what I meant, thank you. Obviously, hitting something (the Earth, the Moon, a stray asteroid, GPS satellite, etc.) would be the end of the journey, but that is not the point.
When I studied these things in secondary school, we called 7.8km/s, "first space velocity", and 11.2km/s, "second space velocity". I think the terms are Russian (pervaya kosmicheskaya skorosty, vtoraya kosmicheskaya skorosty).
I already posted this in another discussion here, but probably it is worth mentioning again. The bigger cousin of X-43A, X-43C, is being cancelled because it does not fit in the new space plans.
So, what's at address 0xfffffff0 when there are only, say, 512MB installed? I realise that when the OS is running, the virtual addresses are translated into physical ones, but presumably at boot time the VM mechanism is still not operational an this 0xfffffff0 should refer to a true physical address. So... ?
This is a bit like programming -- you can write code that is a load of "ugly hacks", or you can write sane, maintainable, clear code. Even if both do the same, the second approach is preferable for obvious reasons. Likewise, in typesetting you can achieve the same visual result with ugly hacks, or with a higher-level approach where you specify intentions and let the tool render them; in the ugly-hacks approach too many things are hard-coded and maintenance/expanding of the code is a nightmare (novices inevitably do that).
My point is that one can improve a lot more by studying the works of the experts as source, rather than as end result.
Tex / Latex is intended as a tool for serious, black-and-white, scientific writing with lots of formulas. It may suck at colour separation, but its math typesettings capabilities are fantastic. The Word's equation editor is a joke in comparison. I tried FrameMaker at one moment and gave up. For instance, putting indices was too annoying in FM, I had to chase some menu items with the mouse, while in Latex I can achieve that by, say, $a_i$.
I agree Letex's typesetting quality is superb and it is the standard in math / comp sci / physics publishing, but it has to develop. I find it amazing that, given its large user base at universities and research centers, there is not enough funding to let several of the core developers devote their energy and time to Latex. See the thread above, F. Mittelbach (yes, that Mittelbach, the author of The Latex Companion) says that Latex 3 has been delayed for years and years, because the core developers are busy with their regular jobs.
Impressive! How did you figure out the URL?
What does "gear" mean in this context? (English is not my first language) A toothed wheel?
The official site of RS-84 does not mention it but it seems to be true. I saw the announcement in usenet .
Thanks.