Top 10 Sun facts

Sometimes the Moon, sometimes the Sun. The Moon's orbit is elliptical, and its apparent diameter varies by 10%. This is why both total eclipses (if the Moon is larger) and annular eclipses (if the Sun is larger) happen.

In January. Earth's perihelion occurs around January 3, and the aphelion around July 4. The distance change is about 3.5%, which gives 6.9% increase in solar energy reaching the Earth at perihelion relative to aphelion. Since the southern hemisphere is tilted toward the perihelion, the southern hemisphere receives more energy from the Sun than does the northern over the course of a year.

Refraction of light in ice crystals. Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Among the best known halo types are the circular halo (properly called the 22° halo), Other common optical phenomena involving water droplets rather than ice crystals include the glory and the rainbow.

Helium was first discovered in 1868 as the unexpected line in the spectrum of the chromosphere of the Sun - and so it was named after the Greek word Helios (Sun).

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.

16 million degrees Celsius. The surface temperature is only 5500 degrees Celsius.

Never. Tropic of Cancer and Tropic of Capricorn mark the northernmost and southernmost latitudes at which the sun may be seen directly overhead. Since the whole Europe is north of the Tropic of Cancer, it is impossible to see the sun at the zenith there.

1839. The first experimental photovoltaic cell has been built by Edmund Becquerel, French physicist aged 19 at the time, in his father garage in 1839. In 1883 Charles Fritts created the first solid state cell.

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.

Within every 225 million years. The sun performs a full turn around the center of our galaxy during 225 million years.