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In September 2025 NASA announced that the number of confirmed exoplanets, planets orbiting stars other than the Sun, had reached 6,000. The first were found only in the 1990s. Most have been spotted by the tiny dip in a star's light as a planet passes in front of it.

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The first confirmed exoplanets were announced in 1992, when Aleksander Wolszczan and Dale Frail found two planets a few times the mass of Earth circling a pulsar, the dense, spinning remnant of an exploded star. In 1995 Michel Mayor and Didier Queloz of the University of Geneva found 51 Pegasi b, a giant planet orbiting a Sun-like star every four days, which earned them a share of the 2019 Nobel Prize in Physics. It was the first “hot Jupiter”, a gas giant far closer to its star than any planet in our Solar System. NASA's Kepler telescope, launched in 2009, found thousands more, and the TESS satellite has continued the search since 2018. Most planets found so far are between the sizes of Earth and Neptune, called super-Earths and mini-Neptunes, a kind our Solar System lacks. By September 2026 NASA's tally had passed 6,300.

Türkçe oku
NASA, Eylül 2025'te varlığı doğrulanan ötegezegen sayısının 6.000'e ulaştığını duyurdu. Ötegezegen, Güneş'ten başka bir yıldızın çevresinde dolanan gezegendir ve ilkleri ancak 1990'larda bulundu. Çoğu, yıldızlarının önünden geçerken ışığını hafifçe azalttıkları için fark edildi.

Varlığı doğrulanan ilk ötegezegenler 1992'de duyuruldu. Aleksander Wolszczan ve Dale Frail, bir pulsarın çevresinde dolanan ve kütlesi Dünya'nınkinin birkaç katı olan iki gezegen bulmuştu. Pulsar, patlamış bir yıldızdan geriye kalan, hızla dönen yoğun bir kalıntıdır. 1995'te Cenevre Üniversitesi'nden Michel Mayor ve Didier Queloz, Güneş benzeri bir yıldızın çevresinde dört günde bir dolanan dev bir gezegen keşfetti: 51 Pegasi b. İkili bu keşifle 2019 Nobel Fizik Ödülü'nün sahipleri arasına girdi. 51 Pegasi b ilk “sıcak Jüpiter”di, yani yıldızına Güneş Sistemi'ndeki hiçbir gezegenin olmadığı kadar yakın dolanan bir gaz deviydi. NASA'nın 2009'da fırlattığı Kepler teleskobu binlercesini buldu; TESS uydusu da 2018'den beri aramayı sürdürüyor. Bugüne kadar bulunan gezegenlerin çoğu, büyüklük bakımından Dünya ile Neptün arasındadır. Süper Dünya ve mini Neptün denen bu gezegenlerin Güneş Sistemi'nde bir örneği yoktur. Eylül 2026'ya gelindiğinde NASA'nın listesindeki gezegen sayısı 6.300'ü aşmıştı.

Sources and further reading

Background reading: Exoplanet
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