Goldau via William Turner
Size: 30.5x47 cmMedium: watercolor, paper
A photo of Saturn.
Took by Cassini with COUVIS on June 07, 2004 at 19:50:37.
Detail page on OPUS database.
Here is a list of some curiosities of astronomy and astrophysics. From our solar system to interstellar space.

Ganymede is the largest and most massive moon of Jupiter and in the Solar System. It has a diameter of 5,268 km and is 8% larger than the planet Mercury. Is the only moon known to have a magnetic field.

Neptune, the eighth and farthest planet from the sun, has the strongest winds in the solar system. At high altitudes speeds can exceed 1,100 mph. That is 1.5 times faster than the speed of sound.

Jupiter’s moon Io is the most volcanically active world in the Solar System, with hundreds of volcanoes, some erupting lava fountains dozens of miles (or kilometers) high. Io is caught in a tug-of-war between Jupiter’s massive gravity and the smaller but precisely timed pulls from two neighboring moons that orbit further from Jupiter - Europa and Ganymede.

The stronger the magnetic field, the larger the magnetosphere. Some 20,000 times stronger than Earth’s magnetic field, Jupiter’s magnetic field creates a magnetosphere so large it begins to avert the solar wind almost 3 million kilometers before it reaches Jupiter. The magnetosphere extends so far past Jupiter it sweeps the solar wind as far as the orbit of Saturn.

A red giant star is a dying star in the last stages of stellar evolution. In only a few billion years, our own sun will turn into a red giant star, expand and engulf the inner planets, possibly even Earth.

Supernovas can briefly outshine entire galaxies and radiate more energy than our sun will in its entire lifetime.

The rotational rate of this massive black hole is one third of the maximum spin rate allowed in General Relativity. This 18 billion-solar-mass black hole powers a quasar called OJ 287 which lies about 3.5 billion light-years away from Earth.

Olympus Mons is a big volcano. It is almost unimaginably huge. It is 550 kilometers (342 miles) across at its base, and the volcanic crater (the technical term is ‘caldera’) at the peak is 80 kilometers (53 miles) long. If you were standing at the edge of the caldera, the volcano is so broad and the slopes are so gradual that the base of the volcano would be beyond the horizon. That’s right, it is a volcano so big that it curves with the surface of the planet.

A neutron star has a mass of about 1.4 times the mass of the sun, but is not much bigger than a small city, about 15 km in radius. A teaspoon of neutron star material would weigh about 10 million tons. The gravitational field is intense; the escape velocity is about 0.4 times the speed of light.
The collapsed star is so dense that electrons and protons do not exist separately, but are fused to form neutrons. The outer layers form a rigid crust surrounded by an atmosphere of a highly energetic electrons and excited atoms.

Gravitational waves are ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe. Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity. Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond).
Credits: Wikipedia: [1,2], laspe.colorado / NASA, Futurism.com [1,2] / LIGO & Universetoday.com