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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.
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|| 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 || 0.6
7 || 380 MeV || relativistic ||
|| 250M || 0.83 || 500 MeV || 4 m
W/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

https://upload.wikimedia.org/wikipedia/commons/7/74/Local_Interstellar_Clouds_with_motion_arrows.jpg

InterstellarMedium (last edited 2015-10-14 02:24:00 by KeithLofstrom)