Planets of our Solar System: Neptune

Hi,
here it goes, here it comes the last post for the series: Planets of our Solar System, maybe if you discover new one I will mention it.
Ok so today I am going to write about Neptune, the eight planet of Solar System, you will see how much we now about thing which is so far away, lets go!

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As I said, Neptune is eight planet and the last once since Pluto is no longer considered to be planet (I will make sure to write epitaph about him).

It was discovered not by accident but by math. When Uranus was discovered and its motion across sky was calculated astronomers saw that it is not on the place where it should be. This was because of Neptune which is influencing Uranus. This happened in the year of 1846 and was discovered by Johann Gall and astronomy student Louis d`Arrest.
Neptune was named after Neptune, the roman god of sea. Greek equivalent is Poseidon of course.
Neptune orbits at the distance of 4.5 billions kilometers. Its radius is 25,000 km and he is little smaller than Uranus but much denser.
He gets 1\800 of the Suns energy as we do and as other gas giants in our Solar System he is radiating more energy than recieving, 2.7 times more.
Interior of Neptune is similar to Uranus`s.
The core makes up two thirds of the planets radius and is made up of rock, ice and some iron and nickel silicates.

Mantle is similar to Uranus`s and there are also probably small diamonds created from methane molecules.

Atmosphere is made up of hydrogen and helium but because Neptune is ice giant there is only  80% of hydrogen and 19% of helium. There is also methane which creates the same effect as on Uranus, it absorbs red light which makes the planet blue. Atmosphere also makes 5 to 10 % of planets weight.
The atmosphere is much more violent than Uranus`s. There are frequent storms and as far as I know they (not counting solar winds :D) are fastest in Solar System.. 2000 kmh. When Voyager 2 flyed around Neptune it saw a giantic storm in its atmosphere. It was similar to Red Giant Spot which is on Jupiter. It was called Dark Giant Spot and it soon dissapeared but some other stormy features appear often (You can see it on the picture).
On the surface is temperature higher than on Uran, about -213°C.

Neptune has magnetosphere and it is as strange as the one on Uranus. It is moved by about half of planet`s radius which astronomers think can be feature of all ice giants. Neptune also has aurora.

There are 5 known rings of Neptune and 14 moons about which I will talk  in future episodes of Moons of our Solar System, so stay tuned.

Dragallur

Pictures taken from wikipedia and http://astronomy.wikia.com/wiki/Neptune_Project and http://spaceplace.nasa.gov/review/solar-system-scramble/scramble-text.html

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Planets of our Solar System: Saturn

Hi,
again I am returning to series about planets, this time it is Saturn. Saturn or Kronos in Greece was titan in greek mythology, son of Uran and Gaia.
Saturn is second largest planet in our system. It is also gas giant so you wont find there any solid surface, but there is solid core in the middle.
Kronos orbits in 9-10 AU from Sun which makes him rotate 29.46 years (that is why is was mentioning in post about transit photometry why you can not find such exoplanets by this method).

Saturn is the most flattened planet and it is because of really fast rotation (day is 10.5 hours long) and because of mettalic hydrogen which is just around the core (you can flatten much easily something liquid then solid).

Also Saturn is the least densest planet. It´s actually so not dense (what is opposite of dense?) that it would flow on the water, its density is: 0.687 g\cm3. This also does not help its gravity which is 0.91 of Earth´s on the equator.

On the northern pole there is this hexagonal “structure” which was for the first time with rest of the planet fotographed by Voyager 1 and 2 (you can see it one the gif). It is assumed that it is created by specific flow of gases and their interaction.

In the year of 2010 there was observed enormous storm running around whole planet, it had to have about 300,000 km.

Now as you can see on the first and third picture and as you surely know Saturn of all four gas giants has the biggest planetary rings. They could be made by some huge asteroid torn apart.
Those rings are 250,000 km from one side to other and only 10 meters high!

There is actually more of them “d” is the closest to Saturn, then comes “c”, the thickest “b” and “a” and “f”. There are two main gaps: Cassini division which is named after our satellite orbiting Saturn and Encke named after the guy who was observing rings.

Saturn has 62 moons as far as we know. The largest is Titan and I will make sure to make posts about some of the most important one´s and probably I will even write post only about the rings.

Only one last interesting thing: when some of the moons are little bit out of normal orbit, rings start to make “waves” which can be kilometers high.

Dragallur

Sources of data and pictures and some more stuff to read about:
https://en.wikipedia.org/wiki/Saturn
https://en.wikipedia.org/wiki/Cronus
http://www.wired.co.uk/news/archive/2013-09/04/saturn-hurricane-water-ice
https://en.wikipedia.org/wiki/Rings_of_Saturn#Encke_Division
+ amazing video by Crash Course (Saturn)

Moons of our Solar System: Deimos

Hi,
today I will write about even smaller moon than Phobos. This time it is Deimos, again named after kid of Ares (Mars) and Aphrodite (Venus). Deimos was the god of terror/panic/dread. Radius of Deimos is 6.2 kilometers which is almost half of Phobos. This guy was also found by Asaph Hall but 6 days earlier than Phobos.

Deimos is even farther away from his father. When we would watch him from Mars´s surface we would see just a small point and in full Moon he would be bright about as Venus from our point of view, otherwise he could look like ordinary star.

On the GIF you can see Deimos hiding behind much larger Phobos. Its surface should be similar to his brother´s but instead it is much smoother which is made by “sand” which smooths everything out over time.

There are only two features named and those are craters Swift and Voltaire named after writers who speculated about moons around Mars even before anybody new they are there.

Its original is not really sure. Usually you will find that Jupiter´s gravitation threw both moons toward Mars and he caught them (this would one reason for so circular orbits of both moons) but most likely they are his kids anyway.

And again his escape velocity is 20.16km/h so if you can run 50 meters in less than 8 seconds you will be able to left him… if it would work like this.

Dragallur

If you have not read about Phobos yet, you should!

https://en.wikipedia.org/wiki/Deimos_(moon)
http://mars.nasa.gov/allaboutmars/extreme/moons/deimos/
http://www.seasky.org/solar-system/mars-deimos.html

Moons of our Solar System: Phobos

Hi,
today I will write about second moon. This time it is Phobos, the bigger of the two moons of Mars.
His name comes from the son of Ares (Mars) and Aphrodite (Venus). Phobos is really strange, he orbits closer to its planet than any other moon. Every year it is closer by 2 meters so one day, about 50 million years in the future Phobos will either crush onto
Mars´s surface or he will be ripped by tidal forces so only ring will be left of him.

Phobos was found in the year of 1877 by Asaph Hall. His surface is one of the darkest of any object in our Solar System (this picture has enhanced colors). There are lot of craters and the biggest has almost the same diameter as whole Phobos. You can see it on the right of the picture and it is called Stickney crater after Asaph´s wife. Temperatures can go from -4°C to -112°C.

Phobos has too low gravity so he could not round himself, that is why he looks as potato. Escape velocity from his surface is 41km/h which means that Usain Bolt would be able to run into space on his own feet. The gravity is 0.000581 of gravity on Earth.

Phobos is small but even than he weights about  10,658,529,896,187,200 kg (or 10.6 quadrillion).

One more strange thing about him is that he is orbiting faster than Mars turns around his axis so he can be seen thrice a day rising from west and setting east.

Dragallur

PS: thanks for those who are reading my blog, I have written 50 posts already!

Planets of our Solar System: Jupiter

Hi,
lets see what we got here, the biggest planet of our Solar System into which all other planets would fit with space to spare. It is Jupiter, named after Roman god of gods or Zeus in Greece mythology.

It is nine times wider than Earth but its mass is 1300 times larger. It is the fastest spinning planet, one day on Jupiter is 10 hours long which makes him 6% less like a circle. Mean distance from Sun is 800,000,000 km or 5.2 AU.

Jupiter is the closest gas giant, which means that he has no surface only thicker and thicker poisonous clouds with various gases. Darker parts are called zones and lighter belts, both of them are rotating in opposite directions. This process is powered by the internal heat of planet (Jupiter loses heat more than he receives) and by fast rotation.
On the picture you can see The Great Red Spot, it is on left of southern hemisphere. That is storm which lasts for decades but now we know that it is shrinking and eventually it will disappear. But for now it is stronger than any storms we ever hope to have on Earth with winds of over 500 km.

When we would dive beneath its deadly atmosphere we would appear in ocean of metallic hydrogen (hydrogen atoms that are sharing their electrons which makes them act as metal). Underneath we are not really sure but there can be solid core of metals and/or rocks.

While Jupiter is really large it is not even close to becoming star, it would have to be 12 times more massive. There exists a theory that Jupiter helps Earth by changing the pathway of comets and other stuff in space but on the other hand it could work in the same opposite way, but still we are not dead yet.

Juno (Hera) spacecraft is right now heading towards Jupiter. In the half of 2016 it will arrive and for 15 months it will collect the most accurate data that we ever had because of its close orbit.

For now there is 65 known moons orbiting Jupiter and I will definitely mention some of them in the future.

Dragallur

PS: be sure to check out Mercury, Venus and Mars!

Planets of our Solar System: Mars

Hi,
today I am getting to fourth planet of Solar System since I skipped Earth.
It is Mars, The Red Planet.

Mars is very pretty planet. There are actually nice conditions, really the best for us if we are not counting Earth of course. This makes Mars very kind of nice for research and everything.
We are able to see him in the morning below Venus but it is not really bright. Still if you have good eye you may be able to see the reddish color of its surface, I will get later to it.

Mars orbits 1,52 AU from the Sun. The difference between closest and furthest distance from our star is over 40.000 km compared to Mercury´s 23.000 km and Jupiter´s 76.000 km.

You wont get overheated very much on its surface, there is average temperature about -60°C. Surface color is red, right you guessed it and it because of iron oxide (hematite). It also makes sense that people named it Mars, after roman god of war (Greek version is
Ares).

There are two main things about physical geography “up” there. Some time in the past Mars collided with huge rock
which made crater over whole north part. Same on the Moon, lava could easily bubble up through thin crust and smooth everything out (as a proof you can see it on the picture). While on the south there are lot of impact craters.

When you see this map immediately your eye moves to huge red spot on the right, those are mountains, actually volcanoes with tallest mountain in the whole Solar System: Olympus Moons which is 27 km tall with surface area about the size of France. This one and also other volcanoes were made when tectonics of Mars were still active.

Really cool thing is in the middle of map, such a small blue line cutting few kilometers to earth. It is Vales Marineris (picture is from Celestia).
This canyon is crack which was made when the crust was cooling. It is 4000 km long, 200 km wide and 7 km deep.

Water on Mars
You have probably heard of it and I will make sure to make separate post about it.
So yes, NASA found liquid water on Mars. Problem is that it is full of soil so you can call it water, yes but it is more kind of mud which is flowing from season to season with its low freezing temperature. There are also polar ice caps on the poles with little water on them and mostly dry ice (CO2).

Even that Mars has atmosphere, it is extremely week and when it is winter on Mars one third of it is in solid form on surface.
Scientists are sure that there was liquid water before (even oceans) but it evaporated and solar winds blew it away because Mars´s gravity was not strong enough to hold it (Mars has only 0,3G).

Mars has two moons but I will talk about them in different episode since I made this: “Moons of our Solar System” thing.

Dragallur

I also wrote about visiting of Mars

Previous post about Mercury
Previous post about Venus

Moons of our Solar System: The Moon

Hi,
since I have done first two planets of Solar System I would go to the Earth but I find it not so important for me 😀 so I will do the Earth´s partner, the Moon.

Our Moon is largest compared to other moons with their planets.
It has radius of 3470 km compared to Earth which has 6378 km. Moon is orbiting about 380 000 km far away while Earth orbits Sun in 150 000 000 km.

First of all. It is assumed that the Moon was created by extremely huge impact of some planet about the size of Mars which collided with Earth. From this collision Moon was born having both material from Earth and from second planet (Theia is it´s unofficial name).
This event made Earth very very hot so when Moon was cooling its closer side to us was
cooling more slowly and when material evaporated it felt on the dark side. This made Moon much thinner on the side turned to us. (Moon is locked by tidal force)

Over eons and eons stuff fell on our brother. When something collided on the thinner side it was much more common to break through thin layer of the surface so lava could bubble up. When this happened couple of times places called mares (marines) were created, this could not happen on the other side because of its thick crust.

There are lot of different structures on the surface. Dark one are marines, there are also craters and lines from old lava flow or even small canyons and places where it is thought that can be milliards of liters of water in the form of ice. Moon is not geologically active but there is still some liquid lava inside, even after 4.5 mld years.

Dragallur

PS: I saw the blood moon and it was amazing!

Planets of our Solar System: Venus

Hi,
here it comes here it goes, post about planet just little smaller than Earth with atmosphere so dense that… well it is very very dense.

But first things first: Venus is second planet from Sun. It is sometimes called “The Evil Twin of Earth”. It is rotating around its axis in the opposite direction from other planets which means that Sun rises there on the west and sets on the east. It is rotating extremely slowly so its day is longer than its year (224:243).
Because of this Venus is also most round planet of all planets in solar system, because no strong centrifugal force is expanding planet at the equator.

Venus is third brightest object on the sky after Sun and Moon. She is easy to see right after sunset and before sunrise.

Even that Venus is 110 000 000 km away from the sun she is hotter then Mercury because of its extremely dense atmosphere which is creating tremendous greenhouse effect (and also pressure which is over 60x greater than our). It is possible that in the past there was water on the surface but positive feedback of greenhouse effect did fast process with it. Now over 95% of Venus´s atmosphere is made up by carbon dioxide. Surface temperatures can rise to over 450°C.

Because of so thick atmosphere it was not possible for long time to observe her surface but now thanks to radars we know that there are over 100 000 volcanoes and 167 of them have diameter greater than 100 kilometers. Structures here are named after women or goddesses from different cultures.

Scientists are not really sure why but sometimes there are holes in the atmosphere through which we can see “down”. Every 100 years or so happens the transit of Venus over Sun. It happens in pairs which are 8 years apart and those who missed it as me are very unlucky since next one will be in the year of 2117 (it is so rare because Venus´s orbit is
moved by 3° so it is usually “above” or “below” us.)

Dragallur

Planets of our Solar System: Mercury

Hi,
here it is, thing I wanted to do a long time: first post about first planet of our lonely Solar System.

Mercury, it is the first and closest planet to Sun. It means one simple thing, it is freaking hot.. but not always.. actually it is not that hot but you would die there, that´s for sure.

Mercury has second highest density of planets in our SS. Right after us. It has pretty big metal core and gravity there is almost the same as is on Mars which is much larger.

The name is same as for Roman god of messengers and travelers. It has strangest orbit of all planets, most elliptical since when you look on other planet´s it looks like circle. Here Mercury is moved by great distance: in Perihelion (close to Sun) it is 0,307 AU away but in Aphelion 0,467 AU. Also orbit is declined by 7° from Earth´s orbit.

This huge piece of rock has really weak exosphere and also really weak magnetosphere. Magnetosphere is probably so weak because axis of Mercury is only 0,1° declined while our is 23° or so… There is no stable atmosphere because Mercury can not hold it from solar winds.
Solar winds are so strong here that they are probably eroding planet´s surface.
Even that there are extreme temperatures so one would except that all water would evaporate but in cracks on poles there are actually tons of tons of water ice!
On the side turned towards Sun can be over 450°C while on the other there is below -170°.

Mercury is not geologically active. It´s year lasts 88 days and day 58 Earth days. This and elliptical orbit create really strange event. When it is about midday on Mercury, Sun stops and for few days it goes backwards and then again it goes in the right way.

Most craters are named by artists and one of them is named Tolkien. There is also one of the biggest craters in whole solar system with 1600 kilometers across and it is called Caloris Basin.

First satellite which mapped the surface was Mariner 10 but much better data was send by Messenger.

Dragallur