Encyclopedia > Hydrostatic equilibrium

  Article Content

Hydrostatic equilibrium

Hydrostatic equilibrium occurs when compression due to gravity is balanced by outward pressure.

In any given layer of a star, there is a balance between the thermal pressure (outward) and the weight of the material above pressing downward (inward). This balance is called hydrostatic equilibrium. A star is like a balloon. In a balloon the gas inside the balloon pushes outward and the elastic material supplies just enough inward compression to balance the gas pressure. In a star the star's internal gravity supplies the inward compression. Gravity compresses the star into the most compact shape possible: a sphere. Stars are round because gravity attracts everything in an object to the center. Hydrostatic equilibrium also explains why Earth's atmosphere does not collapse to a very thin layer on the ground and how the tires on your car or bicyle are able to support the weight of your vehicle.

All Wikipedia text is available under the terms of the GNU Free Documentation License

  Search Encyclopedia

Search over one million articles, find something about almost anything!
  Featured Article
TLAs from EAA to HZZ

... GBF[?] GBG[?] GBH[?] GBI[?] GBJ[?] GBK[?] GBL[?] GBM GBN[?] GBO[?] GBP GBQ[?] GBR[?] GBS[?] GBT[?] GBU[?] GBV[?] GBW[?] GBX[?] GBY[?] GBZ[?] GCA[?] GCB GCC GCD GCE GCF[?] ...