For Questions That Don't Merit Their Own Thread

[Kryten]

As for launcher capability, direct insertion either requires higher engine restart capability and overall stage lifetime for the existing upper stage, or a small additional stage.

[Sorry for double post, forum wouldn't let me edit on mobile]

[JebKeb]

What are all the compounds in petrol and diesel? As in, list of things like octane, benzene, ect... I know the ranges of compounds, but what are they? I'm not talking about additives. I mean the actual constituents.

[p1t1o]

2 hours ago, JebKeb said:

What are all the compounds in petrol and diesel? As in, list of things like octane, benzene, ect... I know the ranges of compounds, but what are they? I'm not talking about additives. I mean the actual constituents.

It is literally a range of compounds. There is no set of fixed percentages. Produced by fractionation, the exact end composition depends on the source of the crude/heavier fraction. It is impossible to boil off single substances, small proportions of other substances will always be present.

To help illustrate - you know how when sometimes you cook with alcohol - like with wine or something? And someone will say something like "The alcohol boils off." Well, this isn't really true. If you boil wine, or some other alcohol/water solution, the boiling points are so close together that you essentially boil them both off at the same time with the proportionally smaller components boiling off proportionally slower - in other words you *are* boiling off the alcohol, but the rate at which water boils off too pretty much cancels it out.

Similar thing happens in a fractionating column when manufacturing petrol - the idea is that you seperate out things that are pretty much similar to octane, what you end up with is something that is mostly octane, but is in fact a mixture of a range of similar chain lengths and branching arrangements, cyclics etc..

 

Related note - this goes some way to explain why petrol comes with an "octane rating", a measure of how easily the fluid will ignite, as compared to a sample of pure octane. Petrol is not pure octane, but it is useful to know how close to octane it will behave. An octane rating is quite closely related to the percentage of octane present, but due to the varying nature of the mix, not an exact match. But it is more than enough to know that it will ignite under such-and-such conditions and liberate X-amount of joules.

Edited May 11, 2016 by p1t1o

[Kryten]

It's even more complex than that, because product of simple fractional distillation (usually called naptha) won't run a modern engine, the octane rating is too low. Parts of it are sent through catalytic crackers, reformers, hydrocrackers, et.c. and then blended together until it has the right proportions of aromatics, alkenes and alkanes. The end proportion isn't fixed either, it's adjusted depending on factors like the climate of the country it's being sent to and the time of year.

[shynung]

2 hours ago, Kryten said:

The end proportion isn't fixed either, it's adjusted depending on factors like the climate of the country it's being sent to and the time of year.

Why is the proportion variable? What problem would using a single mix all-year-round would cause?

[Kryten]

4 minutes ago, shynung said:

Why is the proportion variable? What problem would using a single mix all-year-round would cause?

Mainly cold start problems.

[JebKeb]

I'm trying to make fuels through a process called the Fischer-Tropsch process. Here is the basic equation.

(2n+1)H₂ + nCO ---> C_nH_(2n+2) + nH_2O

So if I was trying to produce petrol, would I aim for octane? 

17H₂ + 8CO ---> C8H₁₈ + 8H₂O

I know there would be competing reactions with smaller amounts of the feedstock going off in their own smaller reactions to produce butane and others, but would they produce something usefuel? I think it would need some altering in some way after production. And seperation from the water.

Edited May 11, 2016 by JebKeb

[PB666]

21 hours ago, JebKeb said:

I'm trying to make fuels through a process called the Fischer-Tropsch process. Here is the basic equation.

(2n+1)H₂ + nCO ---> C_nH_(2n+2) + nH_2O

So if I was trying to produce petrol, would I aim for octane? 

17H₂ + 8CO ---> C8H₁₈ + 8H₂O

I know there would be competing reactions with smaller amounts of the feedstock going off in their own smaller reactions to produce butane and others, but would they produce something usefuel? I think it would need some altering in some way after production. And seperation from the water.

Cyclohexane is probably a good choice for rocket fuel. The octane use is not l-octane, but q-octane, its used because the 1-carbon has a hydrogen that is easier to remove, easier ti ignite. 

[JebKeb]

3 hours ago, PB666 said:

Cyclohexane is probably a good choice for rocket fuel. The octane use is not l-octane, but q-octane, its used because the 1-carbon has a hydrogen that is easier to remove, easier ti ignite. 

Eerm, I wasn't talking about rocket fuels...

Still, thanks for that small amount of info.

EDIT: "usefuel" hahahah

Edited May 12, 2016 by JebKeb

[WinkAllKerb'']

Nice new avater Jeb Keb, here's some littl' support:

https://en.wikipedia.org/wiki/Tectonics
+
https://en.wikipedia.org/wiki/Fossil_fuel
+
https://en.wikipedia.org/wiki/Planetary_core

also super lobbies & super lobbies i don't like you, you're a band of freakin a**h*le

wow this planetary core refueling mechanics rules looks complex ...

Edited May 17, 2016 by WinkAllKerb''

[JebKeb]

2 hours ago, WinkAllKerb'' said:

Nice new avater Jeb Keb, here's some littl' support:

https://en.wikipedia.org/wiki/Tectonics
+
https://en.wikipedia.org/wiki/Fossil_fuel
+
https://en.wikipedia.org/wiki/Planetary_core

also super lobbies & super lobbies i don't like you, you're a band of freakin a**h*le

wow this planetary core refueling mechanics rules looks complex ...

Umm, please explain?! I guess the i was a mistake.

Edited May 17, 2016 by JebKeb

[WinkAllKerb'']

just added a thread with some correlated expended stuff ,'') might be slighty moore complicated overall ,) but you get my support // atmo // balance // thermodynamics // atmo,atom/void exchange // overall energetics signature ; )

time to dig the dataZzzZzzZzz with super lobbies and superlobbies ... yipeeeee ... - _ -

Edited May 17, 2016 by WinkAllKerb''

[0111narwhalz]

When you look at the night sky (with appropriate instrumentation), things further away appear redder, indicating they're moving faster, relatively. Based on this, scientists have concluded that the universe is accelerating, because the things further away are moving faster (or something). But if they're further away, that means their image is older, right? Which suggests that, actually, things are slowing down, right?
Please, point out all the flaws in my reasoning.

[Brotoro]

7 hours ago, 0111narwhalz said:

When you look at the night sky (with appropriate instrumentation), things further away appear redder, indicating they're moving faster, relatively. Based on this, scientists have concluded that the universe is accelerating, because the things further away are moving faster (or something). But if they're further away, that means their image is older, right? Which suggests that, actually, things are slowing down, right?
Please, point out all the flaws in my reasoning.

If space is expanding at a CONSTANT rate, then the further away an object is, the greater its redshift, because there is a greater distance of expanding space between us and the object. It doesn't matter that it takes longer for the light to arrive to arrive from more distant objects...you would still observe this.

But we have found that the redshifts of distant objects deviate from the linear relationship expected for a constant expansion rate, from which we learned that the expansion rate has been accelerating.

[PB666]

On 5/24/2016 at 4:06 PM, 0111narwhalz said:

When you look at the night sky (with appropriate instrumentation), things further away appear redder, indicating they're moving faster, relatively. Based on this, scientists have concluded that the universe is accelerating, because the things further away are moving faster (or something). But if they're further away, that means their image is older, right? Which suggests that, actually, things are slowing down, right?
Please, point out all the flaws in my reasoning.

Basically nothing you see in the night sky is significantly red shifted other than the random star that happens to be moving away from us. Most of the red-shifted stuff can only be seen by telescopes built after the 1920s.

This that appear redder in the deep field, such as Hubble Deep Field, appear redder because they are moving, specifically, away from us.

More importantly we are moving away from them those stars are emitting light of one frequency, similar to our sun and we are observing another frequency. If you take an absorption line from hydrogen in the corona of a star, it means you have frequencies of light above and below.  But light can only travel one speed independent of the observer, what happens is that the wavelength we observe, moving away from that star, increases. More importantly its frequency decreases, this makes sense because light is an energy delivery system, if we move away we get less energy per unit time. But this is distorted by quantum mechanics, we observe E = hv. So what we see is the frequencies above and below the absorption line decrease, they have less energy. That is the wave quality of light, but since when we detect light we only detect photons, thus the individual photons have less energy.

Things get redder with distance, at least for a while, if the universe is accelerating or not.

Let me explain.

There is a thing called the Cosmic Microwave Background radiation. The radiation resulted when protons and electrons combined, it was one of the most powerful light events the universe puts forth, had you been there you would have been instantly blinded and cooked by the light, but from our point of view all the sources have moved to the edge of the visible universe and because it has spread so far its now really dim. In fact the CMBR defines the edge of the visible universe. This is important because the Universe is tremendously bigger than the observable universe at least 5 times probably much more, but the sphere defined by the CMBR when it was emitted was tremendously small, it was about a 100th of the size we perceive it to be now, this is because space has expanded. Expanded is the key word, because the expansion implies some aspect of momentum of the massive objects within, the stuff inbetween space-time is expanding. Not an explosion or bang, just material drift and the workings of space-time. The bang part of space is that which preceded the CMBR

These proton-electron couplings emitted ultraviolet light, but this happened at points along a radiating surface (the virtual object that is the shell of our visible universe) at such an radial angular displacement from us that as they are moving outward such as to move away from us. They are moving outward and we are moving outward; everything is embedded in space-time moving outward, even supermassive black holes and this the landmarks of the universe, galaxies, are generally moving away from each other. By the time the high frequency radiation reaches us, from our perspective, it is red shifted so much so that its in the microwave part of the spectrum. These photons have been traveling through different comoving space-times for 13.8 billion of our years.

Hopefully that was not too confusing. That CMBR is relatively uniform across all the observable sky. And if the universe exploded, then this radiation would not be uniform, it would be shaped like a  edge of the head of a cauliflower propagated to cover an entire surface. So prior to expansion scientist have inserted a thing called Cosmic Inflation, this occurred from the central point (they replace this word because it implies something, distance, that may not have existed, with a word called a singularity, to imply its quantum nature and lack of space-time) in fact the only point, of all mass momentum in the universe, a place we cannot either detect or our travel relative to it. The reason we cannot detect it is that during inflation every point moves away from every other point at a rate consistent with distance and time (space-time), it is in fact the point in the evolution when space-time formed (quantum gravity that held the singularity, held being a faux because it implies time, which did not exist), before that our measures of distance and time cease to help us. As a consequence every perspective in our visible universe seems to see itself as the center of that universe, the center of the expansion. From this perspective we are not accelerating from each other or are we?

So according to classical/relativistic physics, such a universe has mass and mass energy equivalents, its rate of expansion should slow dependent on the mass of the entire universe, massive objects attract each other. But the Hubble Deep Field observations revealed that when you get away from the Milky Way about 5 billion light years, deductions of star sizes in galaxies shows that more distance stars are moving away faster than an inflation drift model would predict. The apparent force or faux tensor in the drift model is that energy equivalents(mass and energy) in space time causes it to try to contract, just as the pulse from two merging black holes cause a measurable flex in space-time observed recently. Some other tensor, dark energy, is superseding that force, as a consequence there is a faster acceleration seen. The idea is about 8 billion years after expansion started, the universe started ever so slowly inflating, space-time between galaxies started to move apart at a faster rate. Its not really clear if this is uniform, or only occurs in the most evacuated parts of space, but it was a major game changer in the last 15 years.

So in summary, what we 'see' when you turn the Hubble on the deepest objects in space, and rf antennas looking at the background radiation is a shell first of early galaxies, and then early hydrogen of a sphere that is inside a sphere of unknown size that is our Universe which the 'big-bang' formed. The only thing we can really say, is that the sphere that we can see was once very much smaller, initially expanded outward at a rate consistent with the laws regarding space-time but then, much later, began to accelerate outward. There is a common belief that because space-time is expanding because of two unknown processes, inflation and dark energy (infusion),  the only thing that we can know is that things 'currently' many billions of light years away (the future generations of stars whose galaxies we see in the deepest of the deep-field) were once so close that from a physical point of view they and us were virtually superimposed. But that belief has to be tempered against the basic fact that we cannot observe anything earlier than the CMBR, and that occurred several hundred thousand years after inflation ended, and many models have all kinds of bizarre, exotic things happening in between.*

*Some scientist suggest, that with proper experiments we can see neutrinos from before CMBR, and it might be possible to say something about the exotic material that came into our universe at our earlier time. The general believe is that exotic material eventually decayed into a prolonged dance between matter anti-matter annihilations and high energy gamma formation. At some point our visible universe became filled with matter (not anti-matter), protons, electrons, a few neutrons. These later combined to form atoms and molecules.

 

,

 

 

 

 

Edited May 26, 2016 by PB666

[Findthepin1]

I found a thing on Google Earth and I don't know what it is. It's about 30 metres wide. It looks like a meteorite crater or something. There's a hole at the bottom, or an object, I don't know. I assume it's a hole. It's on a volcano, Mount Takahe. 76°17'13.29"S and 112° 9'45.72"W. You have to zoom really far in to see it clearly (almost to the point where it automatically puts you in street-view), the satellite picture is relatively excellent, but can only do so much. What is the thing?

[0111narwhalz]

2 hours ago, Findthepin1 said:

What is the thing?

Judging by the shadows, the "object" hypothesis seems to be the most promising. Clearly experiments are needed to confirm the hypothesis.

[PB666]

2 hours ago, Findthepin1 said:

I found a thing on Google Earth and I don't know what it is. It's about 30 metres wide. It looks like a meteorite crater or something. There's a hole at the bottom, or an object, I don't know. I assume it's a hole. It's on a volcano, Mount Takahe. 76°17'13.29"S and 112° 9'45.72"W. You have to zoom really far in to see it clearly (almost to the point where it automatically puts you in street-view), the satellite picture is relatively excellent, but can only do so much. What is the thing?

Youre on a shield volcanoe probably the is a gas seep, the sulfuric acid very hygroscopic melts ice. 

[Findthepin1]

Okay, thanks

[p1t1o]

15 hours ago, Findthepin1 said:

I found a thing on Google Earth and I don't know what it is. It's about 30 metres wide. It looks like a meteorite crater or something. There's a hole at the bottom, or an object, I don't know. I assume it's a hole. It's on a volcano, Mount Takahe. 76°17'13.29"S and 112° 9'45.72"W. You have to zoom really far in to see it clearly (almost to the point where it automatically puts you in street-view), the satellite picture is relatively excellent, but can only do so much. What is the thing?

I would be *really* impressed if it sent me to street view...

[todofwar]

This is kind of hard to explain as a question but it's been bugging me ever since I started playing KSP (this is about real life though, not what the game does). Does the longitude of the ascending node move? What forces it to stay constant since Earth is rotating? Does it matter if you launched from Earth or inserted from somewhere else? If my LAN is 45 degrees W, for example, than will my satellite always cross the equator at 45 degrees W or will it slowly drift?

[p1t1o]

1 hour ago, todofwar said:

This is kind of hard to explain as a question but it's been bugging me ever since I started playing KSP (this is about real life though, not what the game does). Does the longitude of the ascending node move? What forces it to stay constant since Earth is rotating? Does it matter if you launched from Earth or inserted from somewhere else? If my LAN is 45 degrees W, for example, than will my satellite always cross the equator at 45 degrees W or will it slowly drift?

From the wiki:

"The longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude, to the direction of the ascending node, measured in a reference plane.[1] Commonly used reference planes and origins of longitude include:

For a geocentric orbit, Earth's equatorial plane as the reference plane, and the First Point of Aries as the origin of longitude. In this case, the longitude is also called the right ascension of the ascending node, or RAAN. The angle is measured eastwards (or, as seen from the north, counterclockwise) from the First Point of Aries to the node."

[todofwar]

7 minutes ago, p1t1o said:

From the wiki:

"The longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude, to the direction of the ascending node, measured in a reference plane.[1] Commonly used reference planes and origins of longitude include:

For a geocentric orbit, Earth's equatorial plane as the reference plane, and the First Point of Aries as the origin of longitude. In this case, the longitude is also called the right ascension of the ascending node, or RAAN. The angle is measured eastwards (or, as seen from the north, counterclockwise) from the First Point of Aries to the node."

That doesn't really answer the question. I know what the term means, I was wondering if it was constant and if so why. Earth's rotation isn't special, if you launched from the moon and entered Earth orbit why should your ascending node rotate perfectly with the Earth?

[p1t1o]

6 minutes ago, todofwar said:

That doesn't really answer the question. I know what the term means, I was wondering if it was constant and if so why. Earth's rotation isn't special, if you launched from the moon and entered Earth orbit why should your ascending node rotate perfectly with the Earth?

It does, answer it I mean.

The ascending/descending nodes do not rotate with the Earth - your orbit, for all practical purposes, is fixed in space and is not affected by Earth's rotation. However the "longitude" in this context is not measured against a fixed point on the Earth's surface (eg: the Greenwich meridian (0^o Longitude) like it is on maps) but rather against a fixed reference direction in space. In our case it is apparently the "First Point of Aries". So whilst your "longitude of ascending node" (as measured against the First Point of Aries) does not change, the actual Earth-longitude over which your ascending node lies, will change as the Earth rotates, covering the full 360^o once every day.

[Wjolcz]

If we were 150 light years from the Sun with today's technology and radiotelescopes would we be able to detect the first artificial radio signals?