The satellite would raise tides in the primary and vice versa. The tides would dissipate rotational energy via Sedna-quakes. Over time, the rotation rates of Sedna and its moon would be such that each would present the same face to the other. So since Sedna's day is 20 earth days long, we might expect a moon with an orbital period of 20 days.
If there's no moon, you have to lose the angular momentum Sedna had when it formed somehow.
The way to create ozone is to break an O2 molecule. This happens at short UV wavelengths, around 200 nm (blue light is around 360, red around 700). Ozone absorbs UV light as long as 320 nm or so.
This means that decreasing the amount of ozone leads to an increase of longer wavelength UV, which can make it to the ground and lead to skin cancer, dead baby frogs, etc. Decreasing the amount of ozone has no effect on the wavelengths which break up oxygen molecules and create ozone in the first place.
Note that it's "OH" and not "H". Your reaction (from the original post) "H + O3 -> OH + O2" is the problem.
H, OH, and HO2 form a family called odd hydrogen. You can come up with plenty of catalytic cycles involving any two or all three of them. When one is "destroyed", like in H + O3 -> OH + O2, what you're really doing is converting it to another odd hydrogen radical. An H is as good as an OH.
The way to really destroy odd hydrogen is to reform water or H2.
HO2? Where are you getting hydrogen dioxide(peroxide)?
It's called a hydroperoxyl radical. The odd hydrogen radicals interconvert between themselves very rapidly through reactions like this:
H + O2 -> HO2 O + HO2 -> OH + O2 O + OH -> O2 + H
Once you break up a hydrogen or water molecule in the stratosphere, all three of these radicals appear almost immediately.
H2 is a very stable molecule. You need to break it up into free radicals before any chemistry can happen. Even if you have an H2 and O2 mixture, you need to start the reaction with something like a flame or spark.
Given a "choice" between forming stable molecules (like H20) and unstable ones (O2, OH-), the more stable will win
Free radicals don't get a choice. They're so reactive they grab onto the first thing they bump into. In the stratosphere, that's much more likely to be an ozone molecule than another free radical.
These catalytic cycles end when radicals recombine with each other to form water or hydrogen:
OH + HO2 -> H2O + O2 H + HO2 -> H2 + O2
If you're inclined to respond , do me a favor and read this first.
Also, there aren't mentions of H2 reactions specifically, but rather lots of reactions involving H.
That's right. You have to break the hydrogen molecule up. There are two common ways to do this:
H2 + OH -> H2O + H H2 + O(1D) -> H + OH
O(1D) is an excited oxygen atom produced when ozone is destroyed by sunlight:
O3 -> O2 + O(1D)
These H atoms can participate in catalytic cycles until they reform H2 or H2O. These are all very fast reactions since H, OH, and O(1D) aren't stable and want to react with something right away.
Obviously I haven't done the work that the paper's authors have, and if they think that stratospheric cooling from water formation is more important for ozone loss then I won't pretend to know better!
I guess what I'm asking is, is this based on theory or experiment? And does it happen easily in the partial pressures, temperatures, and UV environment of the atmosphere at the ozone layer?
The rates of these reactions have been experimentally measured. There's been a huge amount of stratospheric chemistry modeling done over the last 30 years, and they use the measured reaction rates as inputs into the various models.
Well, yeah. There are so many unknowns here that you can't do a detailed study. They just want to get a sense of the issue. All they're saying is, here's something to think about. Finally, what about oxygen leakage?
Any oxygen leakage would be pretty miniscule compared to what's in the atmosphere now.
Partly that. The atmosphere is mostly carbon dioxide, which is heavy enough that it can't normally escape from Mars.
However, since there's no magnetic field, charged particles from the Sun keep crashing into the upper atmosphere and pulling gases off. Mars doesn't have strong enough gravity to keep that from happening. Over billions of years this becomes substantial.
Mars does have an ionosphere, You have an ionosphere when solar radiation strips away electrons from atmospheric gases.
Mars doesn't have a strong magnetic field though. The magnetic field keeps charged particles away from the planet, which otherwise would erode the atmosphere (this is why Mars has a thin atmosphere).
Hard solar radiation does make it to the martian surface, and in the absence of ozone or another long-UV absorber, would be a problem if we ever did terraform Mars. Buy stock in ACME umbrellas now.
The problem is that Mars' rotation & tilt are erratic, and that's due to the absence of a regulator (large satelite).
They're erratic over timescales of hundreds of thousands of years. If we ever do terraform Mars, large swings in the axial tilt will not be on the list of things to worry about.
It depends on what's left after the supernova explosion. If the mass of the remnant is less than 1.4 solar, it's a white dwarf. If it's more than 1.4 and less than 3.2 solar, it's a neutron star. If it's more than 3.2 solar, it's a black hole
Wasn't one of the reasons Congress extended copyrights in the US to bring them in line with the longer European copyrights? What copyrights were those?
Actually, no. Titan's atmosphere is believed to consist mostly of hydrogen and methane.
Actually, no. Titan's atmosphere is mostly nitrogen and then methane.
Any hydrogen that's there comes from methane dissociation and quickly escapes Titan's gravity. However, the hydrogen atoms can't escape Saturn's gravity and form a hydrogen torus along Titan's orbit. There should be some interactions between the torus and Saturn's magnetosphere which Cassini will observe.
Also since Cassini is still far from Saturn the field of view of the image is quite small. It's unlikely there would just happen to be a bright star in that narrow field of view.
The heat source is radioactive decay. The study described in the article made some assumptions about how much radioactive material the core of one of these icy bodies would contain, and suggests that if enough heat is generated, you'd get liquid water somewhere deep down.
Pressure doesn't generate heat. It can affect whether or not something is liquid, solid, or gaseous though.
That's pretty ignorant, man. Those bits might've taken a company 2 years and 10 million dollars to develop. You seem to think the entire cost of a software manufacturer is whatever printing the cd and jewel case cost them.
Now you're putting words in my mouth. I said the cost of duplication is zero, not development. Of course a software company needs to be compensated for its work.
But I'll say it again: copying bits on a hard disk is not the same as stealing a physical object. It's still wrong but it's not the same.
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The satellite would raise tides in the primary and vice versa. The tides would dissipate rotational energy via Sedna-quakes. Over time, the rotation rates of Sedna and its moon would be such that each would present the same face to the other. So since Sedna's day is 20 earth days long, we might expect a moon with an orbital period of 20 days.
If there's no moon, you have to lose the angular momentum Sedna had when it formed somehow.
The way to create ozone is to break an O2 molecule. This happens at short UV wavelengths, around 200 nm (blue light is around 360, red around 700). Ozone absorbs UV light as long as 320 nm or so.
This means that decreasing the amount of ozone leads to an increase of longer wavelength UV, which can make it to the ground and lead to skin cancer, dead baby frogs, etc. Decreasing the amount of ozone has no effect on the wavelengths which break up oxygen molecules and create ozone in the first place.
Note that it's "OH" and not "H". Your reaction (from the original post) "H + O3 -> OH + O2" is the problem.
H, OH, and HO2 form a family called odd hydrogen. You can come up with plenty of catalytic cycles involving any two or all three of them. When one is "destroyed", like in
H + O3 -> OH + O2,
what you're really doing is converting it to another odd hydrogen radical. An H is as good as an OH.
The way to really destroy odd hydrogen is to reform water or H2.
HO2? Where are you getting hydrogen dioxide(peroxide)?
It's called a hydroperoxyl radical. The odd hydrogen radicals interconvert between themselves very rapidly through reactions like this:
H + O2 -> HO2
O + HO2 -> OH + O2
O + OH -> O2 + H
Once you break up a hydrogen or water molecule in the stratosphere, all three of these radicals appear almost immediately.
Ummm....no, no it doesn't.
Ummm....yes, yes it does. Your turn.
H2 is a very stable molecule. You need to break it up into free radicals before any chemistry can happen. Even if you have an H2 and O2 mixture, you need to start the reaction with something like a flame or spark.
Given a "choice" between forming stable molecules (like H20) and unstable ones (O2, OH-), the more stable will win
Free radicals don't get a choice. They're so reactive they grab onto the first thing they bump into. In the stratosphere, that's much more likely to be an ozone molecule than another free radical.
These catalytic cycles end when radicals recombine with each other to form water or hydrogen:
OH + HO2 -> H2O + O2
H + HO2 -> H2 + O2
If you're inclined to respond , do me a favor and read this first.
Also, there aren't mentions of H2 reactions specifically, but rather lots of reactions involving H.
That's right. You have to break the hydrogen molecule up. There are two common ways to do this:
H2 + OH -> H2O + H
H2 + O(1D) -> H + OH
O(1D) is an excited oxygen atom produced when ozone is destroyed by sunlight:
O3 -> O2 + O(1D)
These H atoms can participate in catalytic cycles until they reform H2 or H2O. These are all very fast reactions since H, OH, and O(1D) aren't stable and want to react with something right away.
Obviously I haven't done the work that the paper's authors have, and if they think that stratospheric cooling from water formation is more important for ozone loss then I won't pretend to know better!
I guess what I'm asking is, is this based on theory or experiment? And does it happen easily in the partial pressures, temperatures, and UV environment of the atmosphere at the ozone layer?
The rates of these reactions have been experimentally measured. There's been a huge amount of stratospheric chemistry modeling done over the last 30 years, and they use the measured reaction rates as inputs into the various models.
See http://jpldataeval.jpl.nasa.gov
They are deliberately extaggerating.
Well, yeah. There are so many unknowns here that you can't do a detailed study. They just want to get a sense of the issue. All they're saying is, here's something to think about.
Finally, what about oxygen leakage?
Any oxygen leakage would be pretty miniscule compared to what's in the atmosphere now.
Hydrogen does catalytically destroy ozone.
H + O3 -> OH + O2
O3 + OH -> 2O2 + H
The net result is 2O3 -> 2O2. There are lots of other similar cycles you can come up with.
Actually solar infrared radiation is more dangerous than ultraviolet.
See http://www.eclipse99.com/safety.html
No, actually an oxymoron is two opposites. Like "Army Intelligence".
Or "Fox News".
This is wrong. The center of mass is about 30,000 miles from the earths center, about 27000 miles above the earth's surface.
The earth has a mass 81.3 times as great as the moon. The distance from the center of the earth to the center of mass is then 384000/82.3, or 4700 km.
I don't know where you get your numbers from, but the infoplease reference had it right.
They are not erratic over those timescales. The Martian Axis can swing by as much as 30 degrees on one vector (near-randomly) within 2 solar days.
I don't understand what you mean by this. Do you have a reference?
This is from the European Space Agency:
http://sci.esa.int/content/doc/7c/24444_.htm
Read the "obliquity" section.
Isn't that because it has weak gravity?
Partly that. The atmosphere is mostly carbon dioxide, which is heavy enough that it can't normally escape from Mars.
However, since there's no magnetic field, charged particles from the Sun keep crashing into the upper atmosphere and pulling gases off. Mars doesn't have strong enough gravity to keep that from happening. Over billions of years this becomes substantial.
Mars does have an ionosphere, You have an ionosphere when solar radiation strips away electrons from atmospheric gases.
Mars doesn't have a strong magnetic field though. The magnetic field keeps charged particles away from the planet, which otherwise would erode the atmosphere (this is why Mars has a thin atmosphere).
Hard solar radiation does make it to the martian surface, and in the absence of ozone or another long-UV absorber, would be a problem if we ever did terraform Mars. Buy stock in ACME umbrellas now.
The problem is that Mars' rotation & tilt are erratic, and that's due to the absence of a regulator (large satelite).
They're erratic over timescales of hundreds of thousands of years. If we ever do terraform Mars, large swings in the axial tilt will not be on the list of things to worry about.
So, is this a black hole waiting to happen?
It depends on what's left after the supernova explosion. If the mass of the remnant is less than 1.4 solar, it's a white dwarf. If it's more than 1.4 and less than 3.2 solar, it's a neutron star. If it's more than 3.2 solar, it's a black hole
Think outside the box, or don't think at all.
While I'm thinking outside the box, I'll also be doing more with less, pushing the edges of the envelope, and giving 110% to the team.
Wasn't one of the reasons Congress extended copyrights in the US to bring them in line with the longer European copyrights? What copyrights were those?
Actually, no. Titan's atmosphere is believed to consist mostly of hydrogen and methane.
Actually, no. Titan's atmosphere is mostly nitrogen and then methane.
Any hydrogen that's there comes from methane dissociation and quickly escapes Titan's gravity. However, the hydrogen atoms can't escape Saturn's gravity and form a hydrogen torus along Titan's orbit. There should be some interactions between the torus and Saturn's magnetosphere which Cassini will observe.
Also since Cassini is still far from Saturn the field of view of the image is quite small. It's unlikely there would just happen to be a bright star in that narrow field of view.
Although our Veep Dick Cheney appears to use a TiBook.....
I would love to see that "switch" ad.
Open the gold castle first. There's a sword inside that kills the dragons.
I played this game tonight for the first time in twenty-some years. Amazing how it all comes back!
The heat source is radioactive decay. The study described in the article made some assumptions about how much radioactive material the core of one of these icy bodies would contain, and suggests that if enough heat is generated, you'd get liquid water somewhere deep down.
Pressure doesn't generate heat. It can affect whether or not something is liquid, solid, or gaseous though.
1. Isn't the adjective pertaining to Venus 'venereal'?
Yes, but to avoid the obvious innuendo people tend to derive an alternative based on 'Martian'. i.e. 'Venusian' or 'Venutian'.
You can use "Cytherean" as well.
That's pretty ignorant, man. Those bits might've taken a company 2 years and 10 million dollars to develop. You seem to think the entire cost of a software manufacturer is whatever printing the cd and jewel case cost them.
Now you're putting words in my mouth. I said the cost of duplication is zero, not development. Of course a software company needs to be compensated for its work.
But I'll say it again: copying bits on a hard disk is not the same as stealing a physical object. It's still wrong but it's not the same.