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{{https://upload.wikimedia.org/wikipedia/commons/7/74/Local_Interstellar_Clouds_with_motion_arrows.jpg | | }} {{https://upload.wikimedia.org/wikipedia/commons/7/74/Local_Interstellar_Clouds_with_motion_arrows.jpg | | width=800 }}

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)