Philosophers and astronomers have long speculated about our starry frame, attempting to create a larger vision of the cosmos.

And some astronomers have speculated that supermassive black holes are present in so-called active galaxies, whose cores seethe with hot, violent nuclear activity.

At the time the astronomers did not speculate what the arcs could be, but they appeared to be the largest objects that had then been observed in the universe.

From the time of Chiron's discovery, astronomers speculated that they therefore must be frequently replenished by some outer reservoir.

For almost a decade astronomers have speculated that Beta Pictoris may be surrounded by a planetary system in formation.

Some astronomers speculated that any possible terrestrial planets in the Alpha Centauri system may be bone dry or lack significant atmospheres.

The astronomers speculated that the Great Comet of 1556 and the Great comet of 1264 are the same comet.

Some astronomers have speculated that it may have a rocky core like Earth, with a thin atmosphere.

Because of their extraordinary brightness and small size, quasars are probably powered by matter spiraling into a supermassive black hole, astronomers speculate.

And some astronomer, catching the phenomena in his lens, would speculate upon just what had happened.