Top 10 universe facts

Quasars. A quasar is an extremely energetic source of radiation powered by accretion disc around galaxy's central supermassive black hole. Quasars were much more common in the early universe, as all known quasars are extremely distant.

Gamma-ray bursts are the brightest in the universe, even brighter than the glare of quasars, second only to the brightness and power of the Big Bang. It is believed that arise during disruption of stars by black holes.

11 years. Solar cycles have an average duration of about 11 years. The periodic changes in the Sun's activity include changes of the levels of solar radiation and the number and size of sunspots.

A planet. According to the giant impact hypothesis Earth once collided with a planet of Mars size usually referred to as Theia, a titaness of Greek mythology, mother of Selene - Moon goddess, which is to reflect the believe the collision was an origin of the Moon.

Comet Hale-Bopp. Hale–Bopp was discovered on July 23, 1995 separately by Alan Hale and Thomas Bopp prior to it becoming naked-eye visible on Earth. Comet Hale-Boppit was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997.

Galaxy filaments are the largest known structures in the universe. They group galaxy superclusters, which in turn are formed by cluster composed of galaxies. Hercules–Corona Borealis Great Wall is considered the largest known structure of Universe. It is estimated to span 10 billions light years.

Lower temperature and strong magnetic field. Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection.

Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. Also one of the longest at over 100 degrees, It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake.

88 constellations. The current list of 88 constellations recognized by the International Astronomical Union since 1922 is based on the 48 listed by Ptolemy in his Almagest in the 2nd century, with early modern modifications and additions In 1930, the boundaries between the 88 constellations were devised by Eugène Delporte along vertical and horizontal lines of right ascension and declination.

Comet Swift–Tuttle. In 1866, after the perihelion passage of Swift-Tuttle in 1862, the Italian astronomer Giovanni Virginio Schiaparelli discovered the link between meteor showers and comets. His findings put new light on a subject, and changed the approach of astronomers to comets.