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Pictures on this page: NASA/JPL-Caltech, European Space Agency(ESA), JAXA(Japan), ISRO(India), Russian Academy of Sciences and Harry Rabb.

Solar system

The Sun

Below is Sun 9.11.2011. Sun is a star. Its diameter is 1.39 million kilometers. Distance from Earth is 150 million kilometers. Mass is 333000 times mass of the Earth. Sun makes one rotation in 28 days. Composition: 73.4% hydrogen, 24.9% helium, 0.77% oxygen, 0.29% carbon, 0.16% iron and other elements with smaller amounts. Sun has dark sunspots. There the magnetic field is so strong that it slows down the movement of gas and makes it cooler. The temperature in the surface of sun is 6000 degrees Celsius and in the sunspot it is 5000 degrees. In the core of Sun the temperature is 14 million degrees and the pressure is 225 billion atmospheres. Sun produces energy with the fusion reactions of atoms.

In October 2014 there was a large sunspot group.

Partial Solar eclipse 20.3.2015. The Moon transits the Sun. Images taken in Riihimäki, Finland. Telescope was SkyWatcher 80/600 ED. Camera Canon EOS 550D.

Development of a sunspot group named AR2529 in April 2016

Below is Sun with NASA and JAXA space probes.


Planets of the solar system from Mercury to Pluto. In this image on the left the planets are as they can be seen through the telescope. On the rigth planets are imaged by NASA and ISRO space propes. Mercury has been imaged during day time when Sun was shining on the sky. To see Uranus and Neptune you need binoculars. Pluto has been classified as dwarf planet.
Planet Diameter km Distance from sun km Mass as earth masses
Mercury 4879 58 million 0.055
Venus 12100 108 million 0.82
Earth 12756 150 million 1
Mars 6800 228 million 0.11
Jupiter 143000 778 million 318
Saturn 121000 1427 million 95
Uranus 51100 2871 million 14.5
Neptunus 49570 4498 million 17
Pluto 2320 5914 million 0.0021

Scales in the solar system. Also the largest moons of the planets and asteroid Ceres is included in this scale image.


Mercury has no atmosphere. It rotates around its axis very slowly, in 59 days. On dayside temperature is +467 degrees Celsius and in night side -173 degrees.

Below Mercury is transiting the Sun 9th of May 2016. Telescope Celestron 8. Camera Canon EOS 60Da.

Below is Mercury with NASA Messenger space probe.


Venus has a thick atmosphere consisting of mainly carbon dioxide. Surface temperature is +460 degrees Celsius.The surface is covered with volcanos and lava flows. Part of the volcanos may be active even today.

Below is image series of Venus approaching the Earth year 2017. On left below is Venus imaged on the middle of the day when Sun is shining. Venus is closest to Earth and angular distance from sun was 8 degrees. In the January image Venus was at distance of 115 million kilometers and angular size was 22 arch seconds. On 24th of March image distance is 42 million kilometers and angular size 59 arch seconds. Images were stacked with Registax.

Below is Venus Transiting over sun 6.6.2012.

Below is Venus with NASA and Russian Venera space probes. Russias Venera 13 and 14 landed on Venus year 1982. They worked less than 2 hours on surface until the hot conditions broke them.

The Earth

The Earth and Mars planets are in zone of life in solar system. Average temperature on Earth is +15 degrees Celsius. Range -80..+50 degrees Celsius. When life evolved on Earth the cyanobacteria, algae and plants converted the atmosphere of the Earth to contain Oxygen. This made possible the development of Oxygen breathing animals. Earth has actively moving continental shelves. They have strong influence to conditions on Earth in millions years scale.

Pictures from planet Earth.
Vesijärvi in Lahti, Finland. Raippaluoto in Vaasa, Finland, traces of last ice age. Swiss Alps near Hochenhorn.
Vuokatti. Thingvellir in Iceland, the border between tectonic plates. London.
Yokohama. Gran Canaria. Bergen, Norway.

The Earth from space.

The Moon

Below is Moon 19th of October 2011. Diameter is 3474 kilometers. Distance 384000 kilometers. Mass is only 1,2 percent of Earth mass. The surface of the Moon has stayed quite unchanged after birth of the Solar system. The dark areas are ancient lava-fields. The light areas are highlands. Asteroid impacts have created craters to the surface of the Moon. Also Earth has been impacted by the Asteroids, but erosion process has worn off most of the impact craters. The Mare Imbrium, The Sea of Rains, has diameter of 1156 kilometers. It is surrounded by 7 kilometers high mountains. Area was born 4 billion years ago when an asteroid, with 250 kilometers diameter, hit the Moon. The diameter of Archimedes crater is 83 kilometers and it is 2,1 kilometers deep. The diameter of Platon crater is 109 kilometers and it is 1 kilometers deep.

In the image below the landing sites of the manned Apollo missions are marked. Apollo 11 was year 1969 and Apollo 17 year 1972.

The Apollo 11 landed on Moon 20th of July 1969. First man on the moon was Niel Armstrong, with the famous first words on the moon: "One small step for man, one giant leap for mankind". Apollo 17 in 1972 was the last manned mission to Moon. Apollo 13, year 1970, had an accident and it did not land on Moon: "Houston, We've Got a Problem". In image below is also image of Niel and Barry DiGregorio , who has studied microbial level life on Mars planet.


Mars has thin atmosphere consisting mainly carbon dioxide. Pressure is 0.6% of Earth pressure. Mars was for 2 to3 billion years after birth of solar system a planet with oceans and thicker atmosphere. Now the surface of Mars is mostly dry and the water is mixed to the soil, both as water and as ice. The average temperature on Mars is -63 degrees Celsius. But in equator the day temperatures are +10..20 degrees Celsius. The gravity on surface of Mars is 38% of the Earth gravity. The day at Mars takes 24 hours and 40 minutes. The year on Mars is 686 days. The rotation axis of Mars has 25 degrees tilt, so there are yearly seasonal changes on Mars. Mars, the god of war, has 2 small moons: Phobos(=Fear), diameter 22 kilometers and Deimos(=Horror), diameter 12 kilometers. See also page Life on Mars?

Below is Mars with NASA and ISRO space probes.


Jupiter is the largest planet of the Solar system. It has a thick atmosphere consisting mainly hydrogen and helium. The atmosphere gets thicker as you go deeper. Jupiter has 4 large moons: Io, Europa, Ganymede and Callisto. Io has active volcanos and its colors are produced by sulfur compounds. Diameter is 3642 kilometers. Europa has under ice cover a deep ocean covering the whole moon. Diameter of Europa is 3120 kilometers. Totally Jupiter has 67 moons.

Below: Series of Jupiter pictures 24.1.2013. During the series Jupiter has rotated 40 degrees from right to left. Jupiter rotates around in 9h 55m. And also Jupiter’s four largest moons. The rotation times of moons are: Io 1.8, Europa 3.6, Ganymedes 7.2, Kallisto 16.7.

Below is Jupiter with NASA space probes.


Saturn is also a gas planet. The rings of Saturn are just 20 meters thick and are composed of water ice. On 23.5.2016 Saturn was close to horizon. Saturn's moons Titan, Rhea, Tethys and Dione are visible. Telescope Celestron 8. Camera Canon EOS 60Da.

Below is Saturn with NASA Cassini space probe. Saturn's moon Titan has a thick atmosphere consisting nitrogen and methane. On surface there is methane lakes in -180 degrees Celsius temperature. Titan is the largest moon in the solar system. Diameter is 5152 kilometers. Titan may have liquid water underground. Saturns moon Enceladus has geysers, which spill out water into space. So there is liquid water under ice cover. Diameter is 500 kilometers. Methone is surprisingly smooth to be a small moon (diameter 3km). Saturn has 62 moons. The Cassini space probe by NASA and ESA has circulated Saturn for Years and its Huygens lander landed on surface of Titan.

Saturns moon Iapetus has one side very dark and the other side bright. Diameter is 1492 kilometers. On equator Iapetus has 13 kilometers high mountains going round the moon.

Uranus, Neptune and Pluto

Uranus and Neptune are gas planets. Diameter of Uranus is 51 118 kilometers. Diameter of Neptune is 49 572 kilometers. Dwarf planet Pluto is a system of 6 bodies. Below Uranus, Neptunus and Pluto imaged with Celestron 8 telescope. The specific blue tone colors of Uranus and Neptune are visible.

Uranus has 27 moons; in image below are Ariel, Titania ja Oberon. Neptune has 14 moons; in image below Triton.

Pluto has 5 moons: Charon, Nix, Hydra, Styx and Kerberos. The size of pluto is 2370 kilometers. Pluto has a large moon Charon, diameter 1200 kilometers. In addition Pluto has 4 smaller moons. Size of Hydra is 45 kilometers and Nix is 42 kilometers. Space probe New Horizons by NASA made a Pluto flyby in July 2015. Surprise is that the surface features on Pluto and Charon seem to be fresh, possibly only 100 million years old. Temperature at Pluto surface is -229 degrees Celcius. The fresh surface may consist of nitrogen ice, carbon dioxide ice and water ice. The sky of Pluto is blue.


Comet Lovejoy 2015, Garradd 2011, PanStarrs 2013. Lovejoy on the left in constellation of Andromeda 8.2.2015 with 400mm tele objective. On the middle 15.3.2015 in constellation of Cassiopeia, with Celestron 8 F6 focus. Comets are 'dirty snowballs'. When they come close to sun they melt and vaporize. The water vapor makes a long tail behind the comet.

Comet PanStarrs was closest to Sun 10.3.2013 about distance of 45 million kilometers. It was closest to Earth 5.3.2013 about 165 million kilometers distance. The length of the tail is about 35 archminutes, which is about 1.7 million kilometers at comets distance. It takes over 100000 years for this comet to go round Sun. Picture on 20:16 with Sky-Watcher 80/600 ED telescope. Exposures 4 x 8 seconds, ISO1600. Camera Canon Eos 60Da. Stacked with DSS. Low-left: EF100-400L telezoom lens set to 400mm. Exposure 1 second, ISO1600.

On low-left we see the movement of PanStarrs between 19:43 and 20:16. It has moved about 3.1 archminutes which is about 151000 kilometers at comets distance. So the speed is about 76 kilometers per second.Name of this comet comes from the telescope system which found it: Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). These telescopes monitor the sky to find new asteroids and comets, which could come close to Earth.

Below is comet Churyumov-Gerasimenko by ESA Rosetta space probe and comet Hartley. Philae by ESA landed on Churyumov-Gerasimenko. Rosetta has observed also Oxygen and Methane coming out from this comet


Asteroids orbit the Sun between orbits of Mars and Jupiter. There is thousands of asteroids. Largest of them is Ceres, diameter 1000 kilometers. Vesta is second largest, 560 km in diameter. You can see these with binoculars.

Ceres has interesting white areas in one crater, named Occator. One possibility is that Ceres has liquid salty water under surface and here it leaks into surface. Images by NASA Dawn.

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