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Ordinary matter, everything made of atoms from stars to people, is only about 5% of the universe. About 27% is dark matter, detected only through its gravity, and about 68% is dark energy, which drives the universe's accelerating expansion.

Cosmology

Science

The story behind the card

The first clue came in 1933, when the Swiss astronomer Fritz Zwicky found that galaxies in the Coma Cluster moved far too fast to be held together by the matter he could see; he called the missing mass dunkle Materie, 'dark matter'. In the 1970s Vera Rubin and Kent Ford showed that stars at the edges of spiral galaxies orbit about as fast as those nearer the centre, again pointing to unseen mass. Dark energy came later: in 1998 two teams studying distant exploding stars found that the universe's expansion is speeding up, work that won the 2011 Nobel Prize in Physics. The shares come from the Planck satellite's maps of the cosmic microwave background, the faint afterglow of the Big Bang. What either dark component actually is remains unknown.

Türkçe oku
Yıldızlardan insanlara kadar atomlardan oluşan her şey, yani sıradan madde, evrenin yalnızca %5 kadarını oluşturur. Evrenin yaklaşık %27'si varlığını yalnızca kütleçekimiyle belli eden karanlık madde, %68'i ise evrenin genişlemesini hızlandıran karanlık enerjidir.

İlk ipucu 1933'te geldi: İsviçreli gökbilimci Fritz Zwicky, Koma Galaksi Kümesi'ndeki galaksilerin, görünen maddenin bir arada tutamayacağı kadar hızlı hareket ettiğini fark etti ve eksik kütleye Almanca “dunkle Materie”, yani karanlık madde adını verdi. 1970'lerde Vera Rubin ve Kent Ford, sarmal galaksilerin kenarındaki yıldızların merkeze yakın olanlar kadar hızlı döndüğünü gösterdi; bu da görünmeyen bir kütleye işaret ediyordu. Karanlık enerjinin izine daha sonra rastlandı: 1998'de uzak yıldız patlamalarını inceleyen iki ekip, evrenin genişlemesinin hızlandığını buldu ve bu keşif 2011 Nobel Fizik Ödülü'nü getirdi. Oranlar, Büyük Patlama'dan kalan soluk ışımayı, yani kozmik mikrodalga arka plan ışımasını haritalayan Planck uydusunun ölçümlerinden gelir. Bu iki karanlık bileşenin gerçekte ne olduğu hâlâ bilinmiyor.

Sources and further reading

Background reading: Dark matter
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