Explanation: Why does the Crab Nebula flare? No one is sure. The unusual behavior, discovered over the past few years, seems only to occur in very high energy light -- gamma rays. As recently as one month ago, gamma-ray observations of the Crab Nebula by the Fermi Gamma Ray Space Telescope showed an unexpected increase in gamma-ray brightness, becoming about five times the nebula's usual gamma-ray brightness, and fading again in only a few days. Now usually the faster the variability, the smaller the region involved. This might indicate that the powerful pulsar at the center of the Crab, a compact neutron star rotating 30 times a second, is somehow involved. Specifically, speculation is centered on the changing magnetic field that surely surrounds the powerful pulsar. Rapid changes in this field might lead to waves of rapidly accelerated electrons which emit the flares, possibly in ways similar to our Sun. The below image shows how the Crab Nebula normally appears in gamma rays, as compared to the Geminga pulsar, and how it then appeared during the recent brightening.
Credit: NASA, DOE, Fermi LAT, R. Buehler (SLAC, KIPAC)
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Dulu masa gua kat asrama harian, tahun tahun sebelum Y2K, gua rajin tengok lanigt. Zaman zaman bergetah hingusan lagi. Time tu kira baru nak up jugak la. Baru start sket nak kumpul keset buat koleksi.
Tak buat apa sangat pun. Melepak. Neon kurang sekitar situ menyebabkan langit agak clear. Biasa gua jalankan aktiviti ni lepas magrib sebelum isyak. Perkara biasa yang gua nampak ialah bintang bergerak.
Gua tak tau la, bintang bergerak ke, tuju tuju ke, ufo ke.. yang penting pot ni senyap sikit daripada dalam surau. Bukan bising ngaji, memekak ada la. Sekarang gua tengok pot gua tu, tak de pun yang pot kat situ. Maklum la, surau dah ada ekon.
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