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WonderSpace fact

Voyager 1 and Voyager 2, launched by NASA in 1977, have both crossed into interstellar space, the space between the stars, beyond the bubble of particles blown out by the Sun. They are the only spacecraft known to have got there, and both still send data to Earth.

NASA

ScienceTechnology

The story behind the card

The Sun constantly blows out a stream of electrically charged particles, the solar wind. It carves a vast bubble in space called the heliosphere, whose outer edge, the heliopause, is where the solar wind meets the thin gas between the stars. Voyager 1 crossed it on 25 August 2012 and Voyager 2 on 5 November 2018, both about 120 times farther from the Sun than Earth is. By August 2026 Voyager 1 was some 25.6 billion kilometres from the Sun, and its radio signals were taking more than 23 hours to reach us. It was expected to pass a full light-day from Earth, the distance light travels in 24 hours, in November 2026. Both probes run on electricity made from the heat of decaying plutonium. That supply shrinks every year, so engineers have been switching instruments off one by one to keep them going.

Türkçe oku
NASA'nın 1977'de fırlattığı Voyager 1 ve Voyager 2 yıldızlararası uzaya ulaştı. Güneş'in çevresine saçtığı parçacıklar dev bir kabarcık oluşturur; bu kabarcığın dışına çıktığı bilinen tek uzay araçları bu ikisidir ve ikisi de Dünya'ya hâlâ veri gönderiyor.

Güneş uzaya sürekli olarak elektrik yüklü parçacıklar saçar; bu akıma Güneş rüzgârı denir. Rüzgâr, uzayda helyosfer adı verilen dev bir kabarcık oluşturur. Kabarcığın dış sınırı olan helyopoz, Güneş rüzgârının yıldızlar arasındaki seyrek gazla karşılaştığı yerdir. Voyager 1 bu sınırı 25 Ağustos 2012'de, Voyager 2 ise 5 Kasım 2018'de geçti; ikisi de o sırada Güneş'ten, Dünya'nın uzaklığının yaklaşık 120 katı mesafedeydi. Ağustos 2026'da Voyager 1, Güneş'ten 25,6 milyar kilometre kadar uzaktaydı ve radyo sinyallerinin bize ulaşması 23 saati aşıyordu. Kasım 2026'da Dünya'ya bir ışık günü, yani ışığın 24 saatte aldığı yol kadar uzaklaşması bekleniyordu; bu mesafeye ulaşan ilk uzay aracı olacaktı. İki sonda da bozunan plütonyumun ısısından elektrik üretiyor. Bu güç her yıl azaldığı için mühendisler, sondaları çalışır durumda tutmak amacıyla bilimsel aletleri birer birer kapatıyor.

Sources and further reading

Background reading: Voyager program
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