Space NEWS #2

Hi,
Today I am bringing space news. Just a short ones. So in last post I mentioned gamma-ray bursts. I found out that NASA found one GRB
 graph shows Fermi Large Area Telescope data from August 2008 to July 2015 for gamma rays with energies above 100 million electrhappening over and over again. As you can see on the picture there is real repeating of many and many GRBs.
Those come from black hole, a supermassive black hole from active galaxy 5,000,000,000 light years away.
It has accretion disk but scientists are not sure yet why it is in such a periods so one of many hypothesis is that there is actually second black hole which as its orbits the first one makes changes to the disk which then make some bursts bigger than other.
Dragallur

Gamma-ray bursts

Hi,
today I want to look on some pretty energetic stuff. This time it will be gamma-ray bursts or GRBs.
I was inspired by episode of Crash Course which you can watch here.


GRBs are the most energetic and violent events which as far as we know can occur in our Universe.
They were discovered by accident. In the late sixties USA was trying to detect if Soviets are using nuclear tests even after Nuclear Ban Test Treaty. This treaty was signed by Soviets, UK and USA. It banned to test nuclear weapons except underground. Mostly to reduce the amount of radioctive waste released into atmosphere and to slow down nuclear progress during cold war (on the picture president Kennedy signs the treaty).

So USA was checking if there is any radiation from the atmosphere from Soviets. Indeed there was some radiation but too strange to be from nuclear bomb. It was just a short very strong glimpse of gamma burst.
Soon it was clear that it comes from space but noone was sure what is its source. All of those bursts were far too short so before any telescope turned to the source they disapeared.
Until 1991 when Compton Gamma Ray Observatory was launched practically no progress was made. CGRO was fast enough to rotate when some GRB occured and then it sent coordinates to telescopes on Earth which found out that the sources of GRBs are billions of light years away! This was such a breakthrough because those events was found out gammarayburstenergies2a.gifthat have to be extremely powerful.
But nothing so powerful exists so what they came up with was that when supernova (or hypernova) explodes the energy is lensed in two beams opposite to each other.
This is one type of GRB, the more studied. As you can see on the picture GRBs are only visible if they are pointed toward you which is much smaller fraction of those which actually occur.
The other type is long GRB, those make up of 30% of all GRBs and they are created by merging of two massive objects like two neutron stars or neutron star and black hole.

GRBs are really dangerous. The energy they emit is so high (for example the energy GRB can equal to energy of Sun, released in seconds) that if one of them in Milky Way would be pointed right towards us it would definitely cause mass extinction, like really large one.
Luckily the probability of such event is so low that we will most likely be killed by something else.

While we can see about one GRB per day they happen about once 100,000-1,000,000 years in galaxy of Milky Way’s size. The most distance one was detected to be 30,000,000,000 light years away.

Dragallur

Planets of our Solar System: Uranus

Hi,Uranus.jpg
today lets see some stuff about Uranus!
Uranus was named after the god of sky. It is third largest planet but fourth in mass.
It is special type of gas giant: the ice giant. The difference between him and Saturn and Jupiter is that there is only 83% of hydrogen in its atmosphere.

Uranus was discovered by William Herschel. It is actually the first discovered planet. It is called discovered because it was not known in ancient times and it took a guy and telescope to find him. Some people found Uranus before William but they did not notice the strange movement and marked him as star. Uranus lies right on the edge of visibility by naked eye with apparent magnitude about +5.7 or so.

The interior of Uranus is very specific. There is outer atmosphere as you can see on the picture. There is lot of methane which makes Uranus look blue, methane absorbs red light very well. To see some cool stuff with methane, click here.
It continues to mantle where is water, ammonia etc… by astronomers those things are considered to be ice stuff, which is as strange as that everything else than hydrogen and helium to be considered metal.
Very important is that ice giants don`t have metallic hydrogen inside. The inner core is made up of mostly rock, it is about half the size of Earth.

Because of low inner heat of Uranus there are not many features in the atmosphere while sometimes some clouds and storms appear there. Speaking of storms, there can be winds which have the speed of 900km|h, which is hella lot!

Uranus has magnetosphere. Also very strange because its center is moved by third of his radius. Uranus has probably the strangest rotational axis of all planets in Solar System. It is turned by about 90° as you can see on the next picture.
Astronomers are not very sure why this is, maybe because of some huge impact. On the picture you can see the planetary rings of Uranus. There is 13 of them and they are really thin.
Uranus also has 27 found natural satellites which are named after Shakespear`s characters.

It takes 84.07 years him to go around Sun. Day there is shorter than on Earth with little over 17 hours. The usual distance from Sun is almost 3 billions kilometers or about 20 astronomical units.

Under the thick atmosphere there is a huge pressure which can brake methane molecules appart and form diamonds.
There was only one mission to go around him and it was Voyager 2 so we dont know so much stuff about him.

Dragallur

Picture are taken from Uran czech wikipage.

Space NEWS #1

Hi,
I decided to write about Space NEWS! Most of them probably would be from NASA page.
Today I want to start with WT1190F impact of Earth and then about cloud which was found in Titan`s atmosphere.


First, yesterday 13th November some space debris entered the Earth`s atmosphere.
Most of it burned up in the atmosphere but still it made a WT-reentry-fireball-tight.jpgfireball.
For few years object named WT1190F orbited Earth in more and more eliptical orbit. Finally this object falled down entering atmosphere in 11 kilometers per second. Nobody was in danger because it fell about 100 kilometers south of Sri Lanka.
For some time it was not Trvalý odkaz na vložený obrázekknown if its asteroid or not but finally when its density was calculated astrophysicists were sure that it is hollow and manmade. This event was important for improvment of calculating of stuff falling from the space.
Pictures taken from wikipage about WT1190 and twitter page.

A cloud system called the south polar vortex on Titan's south poleIn Titan`s atmosphere (Titan is Saturn`s moon) Cassini found a giantic storm forming.
Those clouds are about 200 kilometers tall. Cassini used its infrared toll called Composite InfraRed Spectrometer (CIRS).
Those clouds form in very strange way. Not by water evaporating from ground but by flow of gases from warmer pole to the other where those gases sink and in different levels of atmosphere they condensate forming those clouds.
Titan`s seasons last more than 7 years and this is the time when winter starts on Titan`s southern hemisphere.
This page by NASA.

Dragallur

WTF? A conspiracy? 3) Van Allen radiation belt

Hi,
one of arguments by hoaxers is that astronauts would never be able to pass Van Allen radiation belts.

First of all, what are the radiation belts.
Those are belts around whole planet created by interaction of Earth`s magnetosphere and solar wind.
Solar wind is flow of energetic particles from Sun. Those belts were first discovered by James Van Allen.
There are two parts of them. Outer belt which is less dangerous and inner belt where is much more charged particles and especially protons.
It was also proved that there is antimatter in those belts but it is just such a low amount that we would not be able to use it anyway.


Well so hoaxers made up that if human being tried to cross this radiation belt it would kill him. The problem is that it would not, if he went fast enough.

Van Allen`s radiation belts are not stationary which means that there are days when there is more radiation and days when there is less.
Quess when NASA wanted Apollo to fly, huh?
So Apollo 11 went in angle of 30° from equator where the concetration of charged particles was smallest.
The fatal dose of radiation is 1000 rads while the astronauts got from the most dangerous part about 26 rads, which they survived.
This site more deeply explains it.
Most of the charged particles would not be even able to penetrate the space craft. Those which would, would give astronauts a dose about 50mSv. Which is something but it even counts with “higher” number of protons to not going through but all of them shooting the body.
The dosimeters you can check here.

Dragallur

Moons of our Solar System: Ganymede

Hi,Největší měsíc Sluneční soustavy Ganymede
here it comes here it goes, the post about Ganymede.
Ganymede was in Greece mythology really beautiful guy. Zeus decided that he wants him on the Olymp so he made him waiter. Thats about it, Ganymede is only Jupiter`s moon that is named after male.

With other Galilean moons Ganymede was discovered by Galileo in the year 1610.

Now for some facts, Ganymede is the largest moon of our Solar System. It is so large that if he would orbit Sun instead of Jupiter he would be considered planet. Ganymede has greater volume than Mercury, but is not so heavy (has about half of Mercury`s mass).
Still even with such a low density (1,936g\cm3), he is twice as heavy as Moon.

Ganymede is orbiting Jupiter with really small excentricity even that there are other moons which could be distracting his orbit. Orbit distance is about 1 million kilometers and he is able to go around every seven days. As other moons he is tidaly locked to Jupiter.

When it comes to interior of Ganymede it is very interesting. As you can see on the surface is ice crust (and quartz rock). When you check the first picture you can see that there are mainly two shades, lighter and darker. Lighter seems to be newer and without impact craters. Same as on for example Moon or Mars, some tectonic activity probably smoothed everything out.

Right under ice crust there is REAL liquid water! It was found by Hubble Space Telescope when astronomers found out that aurora of Ganymede should be “changing|waving” by about 6° (caused by Jupiter magnetosphere) while it does only by 2° which is by salty ocean which has huge impact because it is electricly conductive. This ocean`s volume is larger than of Earth`s volume, it is 100 kilometers deep.

Ganymede is the only known moon to have its own magnetosphere. It is created by convection of liquid interior of Ganymede (it was first discovere by the satellite Galileo). Convection is process which for example occurs in ocean when cold water goes up where it heats and then sinks again, then its temperature drops and whole process repeats.

Ganymede was created in the accretion disk of Jupiter when whole Solar System began to form. Because he was formed closer to Jupiter than Callisto, liquid and solid parts more easily separated. It took 10,000 years to form him. Example of accretion disk is on the right.

Ganymede, Europa and Io are in orbital resonance. This means that are in some (1:2:4) ratio of orbits. For one Ganymede`s rotation there are two rotations of Europa and four of Io. I found gif of this on wikipedia and I could watch it whole day (not to scale). This resonance also causes heating of their interior because of friction.

First mission to which saw Ganymede from close look was Pioneer 10 and 11. Then Voyager had much better look and finally Galileo (and then New Horizons). For the year of 2020 is planned another mission which would orbit Jupiter.

Dragallur

Sources
https://www.quora.com/Which-moon-is-bigger-than-a-planet
plus wikipedia pages like Ganymede, Orbital resonance..

WTF? A conspiracy? 2) No stars there?

Hi,
so again I continue with another post about conspiracy theory.
Ok, those people who think that Apollo was faked mission give as an argument that there are no stars visible on the photos. This would mean that those pictures are faked because NASA was not able to count where would those stars be from the Moon and rather decided to erase them completely.


Ok as you can see or rather you can not see any stars on this official picture by NASA. Why is this? Well the answer is easy: if you ever tried to taky any photos of something which was in dark, like in forest but you were standing on the field and the Sun was shining, you already know the answer. When you take such photo you wont be able to see practicly anything in the forest, it will be just black while the rest of the image mainly white.

This is what happened on the Moon, you can easily see the stars there the problem is that the camera can not because everything else: the Moon’s surface, Sun, Earth has such greater apparent magnitude that those stars will just dissapear.

Before the end I will just give here the citation from Phil Plait’s Bad Astronomy: “The lunar landscape is brightly lit by the Sun, of course, and your friend is wearing a white spacesuit also brilliantly lit by the Sun. To take a picture of a bright object with a bright background, you need to set the exposure time to be fast, and close down the aperture setting too; that’s like the pupil in your eye constricting to let less light in when you walk outside on a sunny day. ”

Ok that all for me today, hope you guys dont trust those hoax folks.
To read about Flag flapping in the breeze, read this.

Dragallur

Moons of our Solar System: Jupiter´s moons, Prologue

Hi,
today I will continue to write about moons. Now I will be stucked on the moons of Jupiter for while since it seems that there are about 8 worth a separate posts so this will take some time and today I will try to introduce them.

So for now there are 67 confirmed moons of Jupiter which is most in the whole Solar System. They are named after Jupiter/Zeus´s lovers daughters etc.
After while we run out of those names so we started to repeat them with little changes like: Ganymede>>Ganymed
Callisto>>Kallisto and so on. All moons of Jupiter are tidaly locked.
Those moons are in different groups and the most important are Galilean moons.

Galilean moons are four moons discovered by Galileo Galilei. He discovered them in the year of 1610 even that there are some informations saying that before him chinese https://upload.wikimedia.org/wikipedia/commons/5/5a/Galileans.PNGastronomer found them. What is sure is that independently day after Galileo, Simon Marius found them too and he was the one who gave them the names we use now (before we called them Jupiter I, Jupiter II…).
From left to right you can see on the picture: Io, Europa, Ganymede, Callisto. All of them except Callisto interact through gravitation, they heat each other´s interior through friction.

On the right you can see Galilean moons from Celestia with their orbits. The pie graph shows mass of moons.
Second group really worth mentioning is Amalthea group (beatiful name). Those are inner satellites which orbit really closely to Jupiter.
Members of this group are: Amalthea, Thebe, Adrasthea, Metis.

Amalthea PIA02532.pngBelow you can see picture of Amalthea.

On last picture are the other moons with their irregullar orbits, there arises a question how much should they be considered moons when they are so small.

Dragallur

Pictures taken from:
https://en.wikipedia.org/wiki/Moons_of_Jupiter —> here you can find table of all Jupiter´s moons.
https://en.wikipedia.org/wiki/Amalthea_%28moon%29

Info:
Crash Course video Jupiter´s moons

WTF? A conspiracy? 1) Flag flapping

Hi,
last time I talked about a conspiracy about landing on the Moon. Ok I say it is crap and I will try to destroy all the arguments against Apollo 11.
Today I will start with hoax number 1.


Flag flapping in the breeze!

As you can see on this picture there is Neil Armstrong standing next to flag which is said to be flapping in the air, while there is no air on the surface because there is no atmosphere which means no wind.. this is right there can not be any breeze, BUT those people forgot about something.

Ok, so what else could make this flag moving? Right it is the astronaut himself. When Neil or Aldrin took this flag and they put it to the ground they were definitely moving with it and since there is not air friction flag kept on flapping for long time so it looked like breeze. I found video by mythbusters where they show this, plus they test it of course with Earth´s gravity while on Moon I assume that it would be flapping even longer since the gravity would not pull it so much.

Plus if there would be breeze there would be also dust flying around, it is not.

Amy Shira Teitel explains how the flags were constructed so make sure to check it.

There are many arguments so I will explain them one by one in future episodes.

Dragallur

EDIT: The first picture on which it seems that the flag is moving, actually it does not move. The horizontal pole of the flag was not fully expanded and Neil with Aldrin wanted it to look like it is flapping, actually no it is still they did their job really well :D.

Planets of our Solar System: Saturn

Hi,
again I am returning to series about planets, this time it is Saturn. Saturn or Kronos in Saturn (planet) large.jpgGreece 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)