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⇤ ← Revision 1 as of 2015-10-13 04:10:44
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| The [[ https://en.wikipedia.org/wiki/Interstellar_medium | interstellar medium ]] - the coronal gas - forms a column between locations in space. The sun is 4 light years from one edge of a 60 light-year-diameter cloud with a density of [[http://www-ssg.sr.unh.edu/ism/LISM.html | 0.1 hydrogens per cubic centimeter ]], or 1e5 H/m^3^, encountering the sun as it moves towards Scorpio at 25 km/s. Around that cloud is the Local Bubble, 300 LY across with a density of 1e-3 H/m^3^. A light year is 9.5e15 meters, so for the first 4 light years in one direction, and more than 50 LY in the opposite direction, we encounter a column of hydrogen atoms with a density of about 1e21 H/m^2^-LY. That is the density of a layer of liquid water 30 nm thick per light year. 100 light years, 3 micrometers. | The [[ https://en.wikipedia.org/wiki/Interstellar_medium | interstellar medium ]] - the coronal gas - forms a column between locations in space. The sun is 4 light years from one edge of a [[ https://en.wikipedia.org/wiki/Local_Interstellar_Cloud | 60 light-year-across cloud ]] with a density of [[ http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/neighborhood.html | 0.3 hydrogens per cubic centimeter ]], or 3e5 H/m^3^, encountering the sun as it moves towards Scorpio at 25 km/s. Around that cloud is the [[https://en.wikipedia.org/wiki/Local_Bubble | Local Bubble]], 300 LY across with a density of 50 H/m^3^. A light year is 9.5e15 meters, so for the first 4 light years in one direction, and more than 50 LY in the opposite direction, we encounter a column of hydrogen atoms with a density of about 1e21 H/m^2^-LY. That is the density of a layer of liquid water 30 nm thick per light year. 100 light years, 3 micrometers. |
| Line 9: | Line 9: |
| || speed || C || H energy || || m/s || || || || 25k || 8e-5 || 4 eV || || 30k || 1e-4 || 5 eV || || 100k || 3e-4 || 50 eV || || 300k || 1e-3 || 500 eV || || 1M || 3e-3 || 5 keV || || 1.4M || 5e-3 || 10 keV || low energy ion implantation || || 3M || 1e-2 || 50 keV || low energy van Allen belt || || 10M || 3e-2 || 500 keV || high energy ion implantation || || 30M || 0.10 || 5 MeV || || 100M || 0.33 || 50 MeV || high energy van Allen belt || || 200M || 0.67 || 380 MeV || relativistic || || 250M || 0.83 || 500 MeV || 4 mW/m^2^ particle power || |
|| speed || C || H energy || Pressure || || m/s || || || Pa || || 25k || 8e-5 || 4 eV || || || 30k || 1e-4 || 5 eV || || || 100k || 3e-4 || 50 eV || || || 300k || 1e-3 || 500 eV || || || 1M || 3e-3 || 5 keV || 500μ || || 1.4M || 5e-3 || 10 keV || || low energy ion implantation || || 3M || 1e-2 || 50 keV || 1.4m || low energy van Allen belt || || 10M || 3e-2 || 500 keV || 0.5 || high energy ion implantation || || 30M || 0.10 || 5 MeV || 14 || 7 W/m^2^ particle power in Local Cloud || || 100M || 0.33 || 50 MeV || 500 || high energy van Allen belt || || 200M || 0.67 || 380 MeV || 4K || relativistic || || 250M || 0.83 || 500 MeV || 26K || 11 KW/m^2^ particle power in Local Cloud || |
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| {{https://upload.wikimedia.org/wikipedia/commons/7/74/Local_Interstellar_Clouds_with_motion_arrows.jpg | | }} |
Star Travel and the Interstellar Medium particle effects
The interstellar medium - the coronal gas - forms a column between locations in space. The sun is 4 light years from one edge of a 60 light-year-across cloud with a density of 0.3 hydrogens per cubic centimeter, or 3e5 H/m3, encountering the sun as it moves towards Scorpio at 25 km/s. Around that cloud is the Local Bubble, 300 LY across with a density of 50 H/m3. A light year is 9.5e15 meters, so for the first 4 light years in one direction, and more than 50 LY in the opposite direction, we encounter a column of hydrogen atoms with a density of about 1e21 H/m2-LY. That is the density of a layer of liquid water 30 nm thick per light year. 100 light years, 3 micrometers.
These protons will implant themselves in the surface of any object passing through them. At a mere 25 km/s, the energy per proton is 3.6 electron volts - many will bounce off. Approaching the speed of light, the energy approaches multiples of the mass energy of the proton, 938 MeV/c2. That will damage solid structure to the implant depth.
I don't know how much. A particle physicist can tell you how deep.
speed |
C |
H energy |
Pressure |
m/s |
|
|
Pa |
25k |
8e-5 |
4 eV |
|
30k |
1e-4 |
5 eV |
|
100k |
3e-4 |
50 eV |
|
300k |
1e-3 |
500 eV |
|
|| 1M || 3e-3 || 5 keV || 500μ ||
1.4M |
5e-3 |
10 keV |
|
low energy ion implantation |
3M |
1e-2 |
50 keV |
1.4m |
low energy van Allen belt |
10M |
3e-2 |
500 keV |
0.5 |
high energy ion implantation |
30M |
0.10 |
5 MeV |
14 |
7 W/m2 particle power in Local Cloud |
100M |
0.33 |
50 MeV |
500 |
high energy van Allen belt |
200M |
0.67 |
380 MeV |
4K |
relativistic |
250M |
0.83 |
500 MeV |
26K |
11 KW/m2 particle power in Local Cloud |
