"We seem to live in a remarkably economical X-ray universe, in that the observed cosmic X-ray background (CXRB) is pro…"

"LOFAR is a new European radio interferometer operating at frequencies 15–240 MHz (van Haarlem et al., 2013) and repre…"

"The continuum spectrum of a quasar can often be described, over a broad frequency range, by a power law of the form S…"

"General relativity"

"It is worth quoting Anthony Grafton’s summation of Scaliger’s assault on the prisca theologia presumptions of his con…"

"The first Graeco-Egyptian astrologists did not invent the discipline they claimed to teach the Hellenic world. They u…"

"In making his own calculation, however, Christopher Columbus preferred the values given by the medieval Persian geogr…"

"You climb a mountain situated close to the sea or a level plain, and then observe the setting of the sun and find out…"

"The gods living in the north at the Meru mountain (i.e., at the north pole) see the Sun, after it has risen, for half…"

"On any day calculate the longitude of the Sun and the Moon for sunrise or sunset without applying the longitude corre…"