Voyager 1 crosses the heliopause at 121.6 AU
Low-energy particles of solar origin fell away and galactic cosmic rays rose sharply, indicating that the spacecraft had passed out of the solar wind and into interstellar plasma. The interpretation was contested at the time because the magnetic field direction did not turn as models had predicted it would at the boundary, and the spacecraft had no working plasma instrument to settle the question directly.
Observed — measured or witnessed, with the observation cited.
Subjects
- Voyager 1 · mission · Interstellar space, in the direction of the constellation Ophiuchus · not located
- Heliopause · natural phenomenon · not located
- Very local interstellar medium · natural phenomenon · not located
Evidence
Verified — Every field is supported by a cited authoritative source.
In Situ Observations of Interstellar Plasma with Voyager 1
Voyager 1's plasma wave instrument recorded electron plasma oscillations near 2.6 kHz in October–November 2012 and April–May 2013, implying an electron density of about 0.08 cm⁻³ and indicating that the spacecraft had been in interstellar plasma continuously since the boundary crossings of July–August 2012, dated 25 August 2012 at 121.6 AU. V55 verification basis: the paper is on a publisher domain blocked to this session, but search results carried the frequency, the density and the crossing date and distance and attributed them to this paper.
Science (American Association for the Advancement of Science) · 2013-09-12 · Verified
Gurnett, D. A., Kurth, W. S., Burlaga, L. F. and Ness, N. F., Science 341, 1489 (2013), doi:10.1126/science.1241681
Recorded on Voyager 1
- The full Grand Tour is cancelled and rebuilt as a two-spacecraft mission
- Voyager 1 launches
- Voyager 1 closest approach to Jupiter
- Active volcanism found on Io
- Voyager 1 passes Saturn and Titan, and leaves the plane of the planets
- Voyager 1 photographs the solar system from outside it
- Voyager 1 crosses the termination shock at about 94 AU
- Voyager 1 crosses the heliopause at 121.6 AU
- The 2012 crossing is confirmed from plasma oscillations
- Voyager 2 crosses the heliopause at 119 AU
- Voyager 1's cosmic ray subsystem is switched off
- Voyager 1's low-energy charged particle instrument due for shutdown
- Voyager 1 reaches one light-day from Earth
Related
Related because they share a subject in the Atlas — never because the text looks similar.
- Voyager 1's cosmic ray subsystem is switched off · 2025-02-25
- Voyager 1's low-energy charged particle instrument due for shutdown · 2026 (announced plan)
- Voyager 1 reaches one light-day from Earth · 2026-11-18 02:16 PST (computed)
- Voyager 2 crosses the heliopause at 119 AU · 2018-11-05
- The 2012 crossing is confirmed from plasma oscillations · 2013-09-12
- Voyager 1 crosses the termination shock at about 94 AU · 2004-12-16
- Voyager 1 photographs the solar system from outside it · 1990-02-14
- Voyager 1 passes Saturn and Titan, and leaves the plane of the planets · 1980-11-12