Speed of light they appeared 13 billion years ago, when the universe was less than a billion years old. The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the evolution of stars, of galaxies, and of the universe itself. Astronomical distances are sometimes expressed in light-years, especially in popular science publications and media. A light-year is the distance light travels in one year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri,
2-in-1 PC citing the quote below. In April 2012 Apple's CEO Tim Cook, answering to the question of the researcher Anthony Sacconaghi about a possible hybrid of iPad and MacBook, compared a 2-in-1 to a combination of "a toaster and a refrigerator" that "doesn’t please anyone": 2-in-1s are natively supported by the Windows 8, 8.1 and 10, and Chrome OS operating systems. Various other Linux distributions also support some touch features of 2-in-1s, though they are generally unsupported by hardware vendors. 2-in-1 PC A 2-in-1 PC, also known as a 2-in-1 tablet, 2-in-1 laptop, 2-in-1 detachable, laplet, tabtop, laptop tablet, or simply