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.

Changes in Sunspots during five days, 9-13th of September 2021. NASA Solar Dynamics Observatory image on same region in X-ray range, shows the magnetic field lines.

Large sunspot groups , AR 2993 ja 2994, 19-25th of April 2022. 

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

Below is Sun with NASA and JAXA space probes.

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

Mercury

Mercury planet is always a difficult target to observe and photograph from Finland. It is low in horizon after sunset, so that the turbulence of the atmosphere makes the image blurry.  In april 2022 images below Mercury is imaged half hour after sunset in the evening sky. Images are video stacks with Autostakkert 3. In 2012 and 2020 images Marcury has been spotted from day sky. Mercury has no atmosphere. It rotates around its axis very slowly, in 59 days.  On day side 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.

Venus

Venus has a thick atmosphere consisting of mainly carbon dioxide. Surface temperature is +460 degrees Celsius. The surface is covered with volcanoes and lava flows. Part of the volcanoes may be active even today.  Below is image series of Venus approaching the Earth year 2017 and Venus Transiting over sun 6.6.2012. 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.

Venus year 2020

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. 

Mars

Mars has thin atmosphere consisting mainly carbon dioxide. Pressure is 0.6% of Earth pressure.  Mars was for 2 to 3 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. 

Surface features of Mars during five nights  in September and October 2020. The South polar cap is well visible. It is now small and has released large amounts of water vapor to atmosphere. As consequence the large dark areas cover now larger area of southern Mars.

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.

Saturn 

Saturn is also a gas planet. The rings of Saturn are just 20 meters thick and are composed of water ice. Telescope Celestron 8. Camera Canon EOS 60Da. 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.

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.

Comets

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 Atlas C/2019 Y4 in March and April year 2020.

Asteroids

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.

Venus

Earth

Asteroids Ceres and Vesta

Mars

Saturn

Comets