The answers may come in time as the Voyagers continue their race through the heliosheath. They will get help with this summer’s launch of an Earth-orbiting craft designed to collect particles that come through the termination shock. In the meantime, astronomers are reconfiguring their model of the solar system. “Our current magnetohydrodynamic models do not fully describe what is happening,” Stone says.

Collecting Atoms from Beyond
Mapping the thickness of the heliosheath will be the goal of the new spacecraft IBEX, planned for a mid-July launch. While the Voyagers provide on-site evaluation of the heliosheath, IBEX will sweep Earth’s orbit for so-called energetic neutral atoms formed in the inner heliosheath. The atoms start out with a positive charge but become neutral after stealing an electron from another particle. This neutrality enables the particles to travel straight, like Jet Skis across the solar magnetic field. They should provide a global view of how the solar system interacts with the rest of the Milky Way galaxy. Both Pioneer 10 and 11, the other two spacecraft leaving the solar system, stopped communicating short of reaching the termination shock. Ground stations last heard from Pioneer 10 in 2003 at about 82 AU away and last located Pioneer 11 in 2000 at 54 AU away.

This article was originally published with the title Voyagers to the End.

1 Comments

1. 1. John Peacock 04:44 AM 3/3/08

   Physics texts fail to deal clearly with sound waves said to not propagate in a vacuum. In what sense does space transmit sonic waves out to the heliosheath?

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