Habitable zone of a star

habitable zone of a star. Sounds like a comfy place, right? Well it can be. It is at least on (tiny portion of) Earth which is an example of object in habitable zone. Such a „zone“ is important for astronomers, or maybe it’s just important for headlines in newspapers.

Habitable zone in a Solar System based on luminosity.

Habitable zone is an area around star where we, with quite limited knowledge on this subject, think that life could be. The simplest „definition“ is that it’s the area where satellite (such as planet) would be able to sustain liquid water. We cannot be sure of course if life needs it but it is the case for the one that evolved on Earth.

The true habitable zone is something a bit more complicated. The simplest case of a planet would be one that behaves as a black body, that means that it absorbs all radiation (light for example) regardless of its wavelength. This is immediately just an assumption because such a planet does not exist. Earth just as Uranus or Mercury reflect light, the planet’s albedo describes this. Albedo is an attribute telling us how much object reflects light. 0 means that it is a black body and 1 means that it is white body aka perfect mirror.

There are even more factors that one could consider. For example, when planet has thick atmosphere it can sustain liquid water (and life) even further out from habitable zone on the other hand if that happens to planet like Venus which is already pretty close, you have got hell. If satellite orbits with high eccentricity the conditions are again different.

It’s hard to combine all of this together which results in lot of different outcomes depending what model one picks. Estimates for Solar System are between 0.9 or even 0.6 to 1.3, 2 or 3 astronomical units. In most of them Earth is just on the inner edge. These numbers were pulled from Wikipedia.

When we hear in news that a new exoplanet was found in a habitable zone it might not mean much. This news usually come alongside the information that the planet has similar size that of Earth, it’s not like we could travel there or anything, now we are mostly collecting data and learning.


HZ picture: By Habitable_zone-en.svg: Chewiederivative work: Ignacio javier igjav (talk) – Habitable_zone-en.svg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8462897

Problems that we will have to face

Disclaimer: This is my opinion, not advised by anybody, feel free to comment below.


There are two problems that we as humans will have to face. I will write about the two that I think are crucial and only now people start to appreciate them.

The first problem is Global warming. It poses a lot of threats not only to fragile ecosystems but to whole Earth. Some of the effects listed from Wikipedia are: extreme weather, sea level rise, ocean acidification, changes in agriculture, environmental migration and much, much more [1].

Global warming is the first problem that we need to address but in this post, I will concentrate on the next issue on the list. Humanity will eventually die out if we are not able to spread in the Universe [2].

First, we could of course ask the question when we should colonize other planets or even if it is good idea. Let’s take a scenario, when humanity successfully colonizes Mars and at the same time Earth is becoming more inhabitable. At some point, we simply leave it behind, maybe let it rejuvenate without ever learning how to live in a way that does not cause rest of life extinct. What would continue? Maybe we will be able to spread out in the rest of the Solar System and eventually leave it behind. In what state though? And does it even matter if Mars which is right now mostly empty wasteland suffers any damage if it is even possible? Maybe we would change into species that travels the Universe and leaves dead rocks behind? What if we encountered other life out there, would them await the same fate as Earth? We are authors of our own morality and clearly there does not seem to be objective one. Our values change, we are starting to really appreciate our surroundings, the question is, are we fast enough?

Picture of Mount Sharp on Mars, taken by Curiosity rover.


Note: I am aware that there are different things that could happen. I took time today to write shortly out what I thought about one of them.

[1] There are also problems not related to Global warming but are as well very global, for example what are we going to do with plastic.

[2] See also, gamma ray bursts, solar eruptions (big problem but probably no immediate deaths), huge asteroid collisions and other things that would wipe us out.

Red Bull Stratos and its giantic balloon

we all know that helium balloon raises up which makes it such a fun object, most things in every day life do not do that. This attribute can be used to raise objects or even humans quite high, but at one point you get a problem, the atmosphere is less and less dense.

Red Bull Stratos logo.svgRed Bull Stratos was a project involving helium filled balloon and a capsule with human (Felix Baumgartner). In the year 2012 it raised up to almost 40 kilometers and then the skydiver jumped down. He reached supersonic speeds (faster than sound: 1234 km/h).

In my physics class we talked mostly about the balloon because of what I mentioned in the first paragraph. 40 kilometers is very high and the pressure there is only about 0.497325257421 Pa which is basically vacuum since the atmospheric pressure is 100 000 Pa. (I used the barometric equation)

Because of this, the balloon can not rise so high in thinner air even though the helium is lighter than air. There is so little of it that it does not provide the necessary lift and the balloon has to be huge. In this case it had 9 144 000 cubic meters! Thats a huge thing. The problem of course was that it was not lifting up only one human but the capsule with all equipment weighted 1315 kilograms and the material of the balloon had 1681 kilograms[0].

The whole project was kind of supposed to be for science and finding out how body reacts to high speeds and for further development of pressurized suits[1]. At the same time there was a lot of helium used which was then of course lost. Beware because helium is on the list of endangered elements!


Btw. You can check out my Patreon site here!

[0]The helium also has to be lifting itself.

[1]At about 18 kilometers the pressure is so low that the water in human body starts to evaporate (not all because blood is enclosed but for example saliva). I wrote about that in this other post. To survive you need to be in a suit.

Logo source: By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=37329038

Europa Multiple-Flyby Mission

today I am going to write about proposed mission to investigate Europa.

Europa Multiple-Flyby Mission is a plan consisting of orbiter and a lander directed towards Jupiter‘s moon.

The reason why to choose Europa is quite clear. There is probably liquid water under its surface and if one launches such a thing, it might get public’s attention.[1] (Which might be now more important than ever considering how Trump wants to cut down NASA’s budget especially on the most important thing that they do: Earth’s climate monitoring.)

First of all the orbiter, which would be launched in the next decade, would learn as much as it could about the surface of the moon, Jupiter’s magnetosphere (see later), weird water

Composite image of Europa superimposed on Hubble data

This is two images of course. The original does not have the Europa in middle but only black spot. You can see the plumes on roughly 7 o’clock.

plumes and so on. There are 9 instruments together planned.

Instruments on those orbiters are able to collect data faster than we can receive it. This is because there are more mission that need attention of our receivers. Those are not some small receivers but specialized ones and all missions have some time to send information. For example New Horizons, just from its flyby of Pluto kept sending data for some 6 months.

In case of Jupiter oriented mission this might be a problem because Jupiter has extremely strong magnetosphere which will probably damage the instruments in matter of few weeks. This way it is best to get close to Europa and then get away as soon as possible and send the data later. This can not be done for the lander so it really lasts in matter of days. (Yes, it is still a problem even if you cover your equipment under 150 kilograms of titanium as is planned!)

The lander is thing planned even further into future, around 20 years or so. Much can change and we will see what the priorities are at that point.


[1]People will probably get quite excited by mission promising founding signs of extraterrestrial life.

Isolation for long space missions

so I was watching Michael Stevens’s first and only free episode of Mind Field where he was talking about isolation. He mentioned that there were experiments of people in closed systems to test how body and mind reacts to long term isolation.

In 1989 Stefania Follini was for 130 days in a cave without any visitors, she could only communicate via “internet”. She also had books to read and some small animals like mice. Her menstruation stopped at some point, she slept for about 10 hours and was awake for 20-25! Also during the visit she lost 7.7 kilograms. This is not the longest isolation at all.

NASA also did in the last few years isolation of 6 people for 8 and later 12 months. This was to test the team work of the people since they were closed together cabin fever showed up, but they did not have to cancel the mission. In 2007 Russians did experiment called Mars 500 where six males stayed together for even longet rime, 520 days, only artificial light as before, they brought with them books and games or dvds but they had limited connection with outside world.


Eight months in “cabin” (project HI-SEAS)

Michael Stevens on the other hand spent “only” 3 days in isolation, but it was a bit different. He was in soundproof small room with white walls, white and black bottles with food and water, sink and toilet. This had dramatically different effects. He had halucinations and could not really tell apart dream from reality, also at one point he was counting bottles and counted 6 instead of 9 😀

What are such experiments for? You want to know what happens to body if it is thrown out of its rhytm and mind too. When we are finally able to get to Mars we need people that are capable of staying in small spaceship for months and months.


Eating the spiciest natural chilli

last Sunday I was at neighbors with my host family for dinner. We ate some pumpkin soup and then I noticed these nice small peppers piled up in the bowl. Already I heard that it is not good to put them in your food so I decided to take it as challenge and take one. People at the table noticed and warned me that I probably do not want to eat it. I was soon persuaded not to take it and rather wanted my host brother to try it and see how it goes.

Yup, this is what it looks like.

“These peppers are the spiciest natural growing peppers.”
“Oh, ok then.”

He said that he is going to split with me. I finally agreed and stuffed half of the pepper into my mouth with some milk next to me and bread with thick layer of “Philadelphia”


This is called lifesaver.

After few bites it started to burn a lot. It is quite nasty but the real pain came when I swallowed for the first time. When it hurts in the mouth you can just calm it with bread as it touches the sides of your mouth but when you throat starts to burn it is way more difficult. In something like 15 minutes it was over. Not so much because of pain but simply the pepper, I cried a lot but hey it was quite interesting.

If you decide to try it out, there is one thing to keep in mind. The pepper is going to burn more than one time, actually it might burn three times.. you will know what I mean after you eat it 😉

Anyway there is a chart called Scoville scale, I thought I already wrote about it but then could not find it so here you go.

Spicy peppers have inside neurotransmitter called capsaicin. It fakes your feeling as it bounds on the nerves that are responsible for you to experience heat. Capsaicin is not solluable in water which explains why it wont help you to drink it when you eat something spicy. Milk is better and dairy products generally help. HCl of course helps too.

Capsaicin itself has 16 million points on Scoville scale which is about 8 times as much as the spiciest pepper which is right now Carolina Reaper with individuals well over 2 million. The pepper that I was eating is 1.5 million almost (which is average) and it is called Trinidad Scorpion Butch T Pepper.


There is just an empty space

here is the second season of facts I created, enjoy:

1) The highest ionization energy for copper is over 1,000,000 kJ/mole, one mole of copper is approximately 63.5 grams and the energy taken by this process is equivalent to the chemical energy of 160 L barrel of oil. This equals also to 250 kg of TNT.
2) The longest protein known is Titin: C169 723H270 464N45 688O52 243S912
3) The thickness of soap bubble ranges from 10-1000 nanometers.
4) One Japanese engineer memorized 100,000 digits of pi.
5) Marie Curie was the first woman to get Nobel prize in 1903. She is also the only woman that got 2 Nobel prizes and this happened to only three other people and two organisations. Also her daughter Irène got Nobel prize with her husband.
6) Einstein was asked to be the first president of Israel, he refused.
7) Four new elements have their names, the most massive (proton num. 118) is called Oganesson.
8) Carbon has the highest melting point and that is 3823 K. The highest boiling point is for Rhenium and it is stunning 5869 K!
9) Yes I am serious, if you fold regular piece of paper 42 times you will get it on a Moon. (42? This is no coincidence!)
10) Everything is just a space.


PS: This was automatic post, I will not be able to respond to comments until Monday.

My favorite scientists and astronomers

so I came up with this idea of list of people that I admire in science. Those are not usually scientists most like ex-scientists who are writing, blogging, learning students and so on.

I want to start with Phil Plait also known as Bad Astronomer. Why? Because he is famous

skeptic in the science community who is leading the league against Moon hoax. When I was writing about moon landing I cited his work quite a few times. He also wrote the book Death form the skies and he was featured in Crash Course Astronomy which was pretty cool, here are some links:

His blog.

His first blog (mostly bad astronomy).

Crash Course Astronomy

Second person in my list is Neil deGrass Tyson. He is astrophysicist, also sceptic and agnostic. He makes quite often fun of Flat Earth and is pretty cool.


Demonstrating the power of gravity in the response to rapper singing about Flat Earth.

Another of my favorite scientists is Bill Nye. I am pretty sure that you know this one.

Science BOSS.

I actually saw him for the first time in USA in science class but actually listened to some of his talks few months ago for the first time. While he is very popular generally I kind of liked his debate with Ken Ham.. watch it, it is worth the 3 hours when you will witness the worst kind of argumentation in all history of creationism 😉 [1]

I would add Michio Kaku but I did not see so much stuff from him so I will just leave it here.


[1] Check out Ken Ham memes, those are best!

My thoughts on mission Voyager

as the title suggests I will be talking about the mission Voyager 1 and 2. I never mentioned them in separate post until today. It is also connected with my presentation I had on the contest.

What are those missions anyway?

Those are two space missions that had quests to check out furthest planets of our Solar System. Because of rare occasion, Voyager 2 was able to check out 4 planets (+ Earth).

Right now both Voyager 1 and 2 are still capable of transmitting signal because their battery working on radioactive materials is still ok, it is not much though, not pictures or something like that.

Sonda na fotografii NASA

Voyagers are twins.

Both were launched in the year of 1977 and are about 19 billion kilometers away from they Earth.

The thing is that both missions are very cool and they collected lot of data but they also have this “Voyager golden record”. It is record of “The sounds of Earth” which are voices  from various languages and also the plate contains some information on how to play it and where in Universe it was launched from.

I know that this was not the main reason for the mission to be launched but at the same time it was not really well made up.

Above you can see the information on how to play the record. How could anyone in the hell know what is this supposed to do? I mean, how can we know that aliens have similar technology like us and that five pictograms can explain how to use it!

There are also images on this thing! There is image of woman in supermarket, photo of Jupites and so on (you can check it out here).

The left circle explains in binary how fast it should be playing. Than the wave is typical frequency of the sound that should come out and under it is something called “scan triggering” (wut?). The boxes under it represent how the image is made and the circle is the first picture that should appear. The lines represent the position of Sun compared to 14 brightest pulsars out there and the two circles represent two hydrogen atoms.

Though this whole thing seems a bit dumb to me, I at least like that they included piece of uranium so that “alien” can know how long it is flying (via radioactive decay).


Green trail, golden leaf!

this is very abstract title I guess but it summarizes why I did not post last Saturday when I planned, yes I am sorry. Anyway I was on this contest called Green trail, golden leaf which is contest of mostly biology though there is also astronomy, meteorology (not this year) and geology. I was not contestant for the first time, but organizator and I helped with astronomy site.

There are two categories which are basicly for older (10-15) and younger (0-10) kids (numbers are rough). The contest happens in groups of 6 people. They are then walking the trail three at a time, getting points on various sites on various topics and finally their points add up.

In Friday I had actually presentation first. I was pretty happy how I did it except that it was a little bit too long. The problem was that even that the presentation was for roughly 50-60 minutes the kids were discussing and asking questions a lot (which made me happy of course) but finally the presentation was roughly 100 minutes.

I was talking about the view on Earth, geocentrism, heliocentrism, no centrism at all and why the Universe is so big and why people usually think it is not. I followed up with aliens and Fermi paradox, of course wow signal and KIC xx… were also mentioned. In the end I mentioned SpaceX, terraformation of Mars, New Horizons and Voyager.

As I said the presentation was going pretty good as well as the contest itself. For younger kids we had questions like:

  1. Name 3 astronauts
  2. What is astronomical unit and what is light year
  3. Name 3 missions (Apollo and other count as 1)
  4. Name 4 constellations that are visible in Czech Republic
  5. Highest mountain in Solar System and where it is
  6. Where do comets come from?
  7. Difference between meteorite, meteor, meteoroid and asteroid.
  8. … (and other)


For older it was bit more difficult:

  1. What is afelium and perihelium
  2. Name all Galilean moons and give a small info for one of them
  3. What is HR diagram
  4. (Lot of pictures about life time of star)
  5. Draw the orbit of typicall comet and draw both tails and name one place where they come from.
  6. … (and other)

From 12 sites astronomy was the 2nd toughest 😀

Lets see how would you do, I will return to it some other post.