Top 10 stars factsStars quiz
What is the densest substance in the universe?
Neutron star. A neutron star is a stellar remnant of a supernova. Neutron stars are very small, but extremely dense - with a radius of only about 12–13 km (7 mi), they can have a mass of about two Suns.
The closest star to the Sun is Proxima Centauri. In which direction we would need to look to see it in the night sky?
It is not visible at all. Proxima Centauri is a red dwarf and its average brightness is very low. That is why even though it is closest to the Sun, it was discovered not until in 1915.
Which direction was the camera pointing at while taking this picture?
North. The entire celestial sphere seems to rotate slowly around the North-South axis of Earth's rotation. So the camera must have been pointed North or South, depending on the hemisphere the photo was taken at. But the brightest star in the centre must be Polaris, at the south celestial pole currently lacks a bright star to mark its position.
What is the source of the most powerful release of energy in the universe, second in scale only to the Big Bang?
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.
What astronomical object emerges sometimes from supernova instead of a black hole?
Magnetar. A magnetar is a type of neutron star with an extremely powerful magnetic field. The magnetic field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays. As of March 2016, only 23 magnetars are known, with six more candidates awaiting confirmation.
What is the name of the hypothetical last stage of the evolution of Sun-sized stars?
Black dwarf. A black dwarf is a theoretical stellar remnant, specifically a white dwarf that has cooled sufficiently that it no longer emits significant heat or light
Stars of which type are the smallest in diameter?
Neutron stars. A typical neutron star has a mass between about 1 and 2 solar masses, with a corresponding radius of just about 12 km. Some of them (pulsars), rotate as quickly as once per 33-millisecond, so their radius must be very small not to break the light speed limit at the surface level.
What is the stellar day?
23 h 56 min 05 s. Sidereal time is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. It is a time scale that is based on the Earth's rate of rotation measured relative to the fixed stars rather than the Sun.
Which stars live the longest in the universe?
Little stars. Large and super-massive stars rapidly burn out. The lifetime of the blue supergiant is only a few tens of millions of years. Meanwhile, the small red dwarfs emit small amounts of energy and burn out very slowly - it is estimated that they may shine through the hundreds of billions of years.
How many stars are there on USA flag?
50. There are 50 starts on the USA flag, one for each state of the Union. Previous version contained 49 stars. It had been used for 1 year merely between 1959, when Alaska was proclaimed a state, and 1960, when Hawaii got admitted into the Union.