Please help contribute to the Reddit categorization project here


    + friends - friends
    63,263 link karma
    26,898 comment karma
    send message redditor for

    [–] Two Planets getting too close- Worldbuilding! PUSSYDESTROYER-9000 2 points ago in askastronomy

    Well we have come quite close to this. Pluto and Charon are similar enough in size that the barycenter is outside of pluto by quite a bit.

    [–] Two Planets getting too close- Worldbuilding! PUSSYDESTROYER-9000 4 points ago * (lasted edited 19 hours ago) in askastronomy

    Depends on the size and distance. Conceptually it's obvious that a big heavy planet would rip apart a small moon at a further distance than a tiny planet. This is called the Roche Limit and is mathematically defined.

    I highly doubt any intelligent live could have thrived there because generally if a planet/moon crosses the roche limit, then it is screwed because even if it only crosses it periodically (it has a very elliptical orbit), in astronomical timescales it would be destroyed in no time, which I would think would too short for life to form. Life needs some level of stability in order to form, and such an occurrence is not stable. Also, this doesn't consider tidal heating, which occurs when two bodies orbit each other very closely. If two planets orbit each other very closely (but outside the roche limit), then they will get very very hot, perhaps thousands of degrees hot. They don't need a sun to warm up, but can actually keep themselves warm from this tidal heating, so in essence you could have thousand degree planets orbiting very very far from a sun.

    Planet orbits are separate from sun orbits, so it doesn't matter if they have one, two, three, or more stars (although beyond 6-7 and the system in general gets too unstable due to perturbations, but that's another story).

    If planet A and planet B are orbitally bound to EACH OTHER, then there cannot be 2 planets. The less massive one is always the moon, even if they are barely different. Now, if you are saying that they are both planets and only orbit the Sun but occasionally pass by each other because one of them has a wacky orbit, then that would be possible but only in the short term. Eventually they will pass so closely that they rip each other apart (bad for life), or eventually the gravitational forces involved would throw one guy out of the solar system. You can try this with universe sandbox 2, the results can be pretty interesting.

    Yes, this scenario of say Mars at where the moon is, is perfectly possible. In fact the orbit of such an occurrence could be very stable, and because the Moon is pretty far from Mars tidal heating would be minimal. The tides on the ocean would be very big, but not too unstable for life to form. Gravity would be pretty much the same as on Earth and on Mars respectively. Geography shouldn't differ too much either. Life might form on both worlds too.

    If you would like visual aids for your world building, I can provide. Also I rushed my explanation, so if you want more specific details I can also provide.

    And although I have always thought that realism provides a more interesting story, do not let science stop your creativity! Science fiction is always fun to read, and worldbuilding is even funner.

    [–] ELI5: How do betting odds work? PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    I'm not a betting man, but I believe that would mean that you pay a certain amount as the bet and if Rams win, then you keep your bet and get paid an extra 4x the bet. So if I bet 100 dollars and the Rams won, I would get my bet back and win 400 dollars, meaning in the end I would have 500 dollars. If the Rams lost, then I would lose my 100 dollars and have 0 dollars.

    [–] ELI5: How do betting odds work? PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    If you win, you win 750x your bet.

    If I bet 1 dollar, I would win 750 dollars, or 75000% profit

    The odds were supposed to be 750:600, meaning if you bet 600 dollars then you would win 750.

    [–] Earth Orbits a K-Type Binary System. What Might Living Here Look Like? PUSSYDESTROYER-9000 1 points ago in askastronomy

    1) If Earth orbits around both stars (p-type) then they will be fairly close to each other to the observer, so day night cycles would be pretty similar. If earth were s-type then it would also look the same and you would have a slightly (very very slightly , less than what the full moon does) brighter night time at some times of the year because the other star would be too far to emulate day but would be too close to look like every other star unless it was at apoapsis.

    2) Atmosphere would look similar but the light that hits objects would be oranger so instead of everything being fairly close to true color during the day, it would have an orange tint.

    3) I dunno

    4) If it's a p type orbit then the 2 stars will stay close to each other but appear to dance around each other. In fact at some points one star will eclipse the other, making day darker because only 1 stars light is reaching Earth. If it was s type then, like I said, day would be pretty standard with night being a bit brighter. In addition the far away star might also be in view with the main star that the Earth orbits at certain times of year.

    If you would like visual aids I can happily provide.

    [–] Astronomers have discovered a planet twice the size of Earth orbiting the nearby star 40 Eridani — precisely where Star Trek character Spock’s home planet Vulcan supposedly lies. PUSSYDESTROYER-9000 1 points ago in science

    There are many ways a planet could orbit in a trinary system, but it would essentially be the same as a binary system. Here is one way it can orbit, around 2 stars that are very close like this, and the third star would be further away, out of the picture. It can also orbit like this, where the two binary stars are very far apart and have their own systems, and the third star would be very very far away.

    [–] First Chance to See a True Night's Sky - What Should I Look For? PUSSYDESTROYER-9000 1 points ago in askastronomy

    Their new NEXT satellites don't have the same box shape so they won't be the same as the old satellites.

    [–] Messier 107 in Ophiuchus PUSSYDESTROYER-9000 4 points ago in Astronomy

    We think it might be the centers of eaten galaxies. Our Milky Way has a central globular cluster around Sagittarius A*. We suspect that the Milky Way might have eaten up other tiny galaxies and all that remain are the globular clusters.

    [–] First Chance to See a True Night's Sky - What Should I Look For? PUSSYDESTROYER-9000 2 points ago in askastronomy

    Get ISS Detector app and look for some Iridium flares. This is the last year you may ever predictably see them since the Iridium satellite consellation is almost completely deorbited.

    [–] ELI5 How did the Big Bang happen? (For my 6 and 4 year olds) PUSSYDESTROYER-9000 2 points ago in explainlikeimfive

    Yeh I got pretty lazy half way through. Basically it was when photons could travel freely through space instead of getting scattered by plasma.

    As for the galaxies either giant clouds of gas allowed the formation or the early universe had these clumps of matter that clumped with other clumps to form a big clump that went on to produce a galaxy.

    [–] ELI5 How did the Big Bang happen? (For my 6 and 4 year olds) PUSSYDESTROYER-9000 3 points ago in explainlikeimfive

    Yes, the observer sees themself as the center of the universe because the big bang started everywhere.

    [–] ELI5 How did the Big Bang happen? (For my 6 and 4 year olds) PUSSYDESTROYER-9000 7 points ago in explainlikeimfive

    Modern cosmology explores the largest, most difficult ideas in all of science. These ideas, yet difficult, are so simple to ask that even a child can ask them. "Does the universe have an edge?", "How did the universe begin?", "What are we?", and "What will be our universe's fate?" are all questions a child may ask in simpler layman terms like "Where did we come from?" or "What will happen in a trillion years?". You may also notice that some concepts require previous concepts to understand sufficiently. Cosmology is a pyramid: you need to understand what we thought first (the base) before you can understand what we think now (the top, or what we think is the top).

    I will answer "How did the universe begin?"

    Does the universe have an edge? No. Why not? Because it violates common sense. What would the edge be? A wall? Empty space? Nothing? If there were an edge, what would happen if you tried to move past it? Without getting too detailed, scientists have evidence to believe that the universe is infinite other than violating common sense. Now ponder this: if if the universe has no edge, then it cannot have a center, right? That is correct. The universe has no center because it has no edge.

    The sky is dark. Why? If the universe were infinite in size, then if I look at any direction my line of sight must eventually run into a star, so shouldn't the sky be blindingly bright? It's like lines of sight in a forest. Eventually my line of sight runs into a tree.

    This hypothesis makes an incorrect assumption. The universe may be infinite in size, but it is not infinite in age, as many astronomers in the 1800s believed. That must mean that the universe came into existence at some point in the past. The distant stars that should fill the gaps of darkness in the night sky are too far away, and their light has not reached Earth yet.

    In 1929 Hubble made the discovery that distant galaxies are redshifted, and that the further the galaxy the more redshifted it is. (If you do not know what redshift means feel free to ask). This implies that the galaxies are receding from each other, which must mean that the universe is expanding. However, due to the nature of expansion, it will appear as though you are the "center" of the expansion, when in reality, it would appear that way regardless of whether you were on Earth, on the Moon, or in the Andromeda galaxy.

    Based on how redshifted things were Hubble could calculate the approximate age of the universe by rewinding, which was about 14 billion years ago. Early critics called this dumb and mocked it by calling this the "Big Bang". The name stuck, but keep in mind that it wasn't a conventional explosion and that galaxies were flying out from this explosion. Rather, the explosion did not occur in a single place but filled the entire volume of the universe. Think of it more as a big "stretch" rather than a bang. That's right. You can point to any other location and say that the big bang took place over there. This is why redshifting makes it look like you are the center of the universe no matter where in the universe you are: because the Big Bang took place everywhere and invented the concept of space itself.

    The Big Bang took place 14 billion years ago, but we can amazingly look back in time to observe the big bang directly. Remember how light travels finitely? That means the further away you look the further back in time you are looking. The moon is roughly 2 light seconds away, so that means it takes light 2 seconds to reach us from the moon, so we are seeing the moon as it was 2 seconds in the past. The same goes for the Sun, but it is 8 light minutes away. Pluto is about 4 light hours away, so we see it 4 hours in the past. The nearest stars are several light years away so we see them years in the past. Andromeda galaxy is roughly 2 million light years away, so we see it 2 million years in the past. What if we look billions of light years away? You get the very very first galaxies of the universe, which are several billion light years away. What we see is billions of years in the past. What if we keep going? Can we see the big bang? Almost. The big bang made a crazy large amount of radiation, and this radiation is everywhere at roughly 13.7 billion light years away from us because the big bang took place everywhere. This radiation is a blanket that does not allow us to see the Big Bang itself but we can get very close. We call this the Cosmic Microwave Background.

    CBR is essentially a picture of what the universe was when it was 371,000 years old. Without getting too specific, we can see that the CBR shows that the early universe was very hot and very dense. Now you are ready to learn about the Big Bang.

    When I refer to particles, I refer to protons, neutrons, and electrons, which are mass. Photons (note the h), is what light is made of and is essentially pure energy and has no mass. We cannot begin at time zero because no one understands what happens under such extreme conditions, but we can get pretty darn close! When the universe was 0.000001 s old, it would have been filled with photons (filled with energy). The universe had a temperature of over 1 trillion degrees. When photons have enough energy, they can convert into two particles: a normal matter particle and an antiparticle (antimatter, which is 100% real). When antimatter and matter meet, they annihilate and create energy. This energy was in the form of photons, so essentially for the first few millionths of a second of the universe you had a bunch of these photons turning into antimatter and matter, and back into photons.

    When the universe was 0.0001 s old, the universe had already expanded such that the temperature had fallen enough to prevent the formation of matter and antimatter. The particles that did exist combined with their respective matter or antimatter particles and turned back into photons, which could not later become matter/antimatter. It would seem that all of the antiparticles and particles would have been annihilated, but for whatever reason, there was a slight excess of matter particles. This excess roughly 0.000000001% . However, the remaining 0.000000001% of matter that was not converted back into energy (because there was no respective antiparticle left to annhilate) turned into everything we see today: galaxies, stars, you, me, and so on. That is why we live in a universe where there is mostly matter and very very little antimatter.

    Remember when I said particles consisted of protons, neutrons, and electrons? Well at 0.0001 s the temperature was too low to produce more protons or neutrons, but there was still sufficient energy to produce electron and anti-electron pairs because they have 1/1800 the mass of protons and neutrons, so electrons and anti-electrons were being made until about 1 minute old, where the expansion had cooled further to the point that no more electrons or anti-electrons could be made. Similarly to the other particles, for whatever reason there was an excess in electrons such that 1 in 1 billion electrons (0.000000001%) had no anti-electron to pair up with, so we live in a universe with electrons. All the protons, neutrons, and electrons which make up the atoms in the universe were produced in the first minute of our universe's history.

    After one minute the universe was still too hot to make atoms, but by two minutes the universe had expanded more such that we could make deuterium, which is an isotope of hydrogen. By the third minute more rations would turn deuterium into helium. However, no atoms heavier than helium could be built because of how atomic weight works. It's very difficult to explain but essentially for a while the Big Bang could not progress beyond hydrogen and helium. After 30 minutes, the universe (which is still expanding) was too cool for nuclear reactions. At this point about 75% of the mass of the universe was in the form of protons (hydrogen nuclei) and the rest was helium nuclei. Nuclei are the centers of atoms and are the basis for them. This 75% 25% mixture was the composition of the earliest stars that we can see that will arrive a few million years later.

    Now the universe is continuing to expand and cool. Before it was too hot to really do anything with the nuclei. There was just so much radiation from all the heat. Then after about 50,000 years the density of energy in photons was less than the density of gas, meaning that there was sufficient disparities for gravity to be able to make things clump together. This clumping would later form stars and galaxies. After about 400,000 years elections were so far spread apart that there was essentially space for light to spread out. This was when the universe first turned transparent, which is why the cosmic microwave background is around this time.

    Now we enter the dark age, which lasts about 400 million years, when the first stars would form. The universe essentially expanded in darkness at this stage. Finally, as the first stars formed, these stars had almost no metals and were actually quite transparent. These stars would have been extremely massive, very very bright, but very short lived. Once these stars lived out their lives (which were less than a million years), they released enough ultraviolet light to ionize the gas in the universe. Before this ionization all the gas was "neutral" and transparent. Now that the gas was ionized it was not transparent. Now the universe had colors and became more like the stars and galaxies we have today.

    Whew! If you got any questions feel free to ask.

    [–] ELI5: Why does looking at the sun when you have to sneeze help you sneeze? PUSSYDESTROYER-9000 3 points ago in explainlikeimfive

    The Sun triggers the Photic sneeze reflex, which causes sneezing in response to bright light. Unfortunately the mechanism of action is not well known, but we do know that it is hereditary. It is not harmful (other than typical harm associated with sneezing like when operating machinery or in surgery).

    [–] ELI5: When did humans become more compassionate and how? PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    Everyone's compassionate with the virtue of hindsight. What they did in the past was perceived to be compassionate. Perhaps decapitating someone with the guillotine was seen as "closure" and was more merciful than torture.

    Considering the pace that society is evolving I would not be surprised if mundane activities we do today are considered evil or incompassionate. Perhaps in 200 years public nudity will be permitted as a way of "truly expressing one's self", or perhaps pets will be banned because it is a "form of animal slavery". Maybe the future will look back at the Information Age as a very prude society, and sex will be very common among even friends in the future. Those are wild guesses that are associated with openness and liberalism and are probably far from what moral values the future will hold, but you get the idea.

    [–] ELI5 How did the Big Bang happen? (For my 6 and 4 year olds) PUSSYDESTROYER-9000 2 points ago in explainlikeimfive

    Cosmology in general is full of the most intriguing questions known to man. They are so intriguing that the answers can have a sort of religious, spiritual feel to them. What I stated was very simplified, but I can elaborate if you want.

    [–] ELI5: How come we don't use human feces as fertilizers? PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    We do, and it is called "night soil". However it's generally not allowed because it makes things very smelly and it also would spread lots of disease.

    [–] ELI5 How did the Big Bang happen? (For my 6 and 4 year olds) PUSSYDESTROYER-9000 11 points ago in explainlikeimfive

    That's a tough question, but for a 6 year old it would be suffice to say that our worlds best scientists noticed something very interesting when they look at far away stars and galaxies with telescopes. They see that everything is racing away from us. The scientists realized that if they are racing away from us, then at some point those stars and galaxies were next to us. They traced the steps and realized that the universe all formed in one epic moment a long long time ago (13.8 billion years ago). Unfortunately there isn't a consensus on what happened to start the Big Bang, or if there was anything before the Big Bang.

    [–] ELI5: Web development: OOP PHP - Classes, Objects, etc. PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    For the first question, yes.

    An object is a specific instance of a class, and are two seperate things.

    Let's say I want to make a triangle. I will first create a triangle class which has some properties, like a variable for height and a variable for width. Then, if I want to implement my triangle for actual use (when it's a class it's just sitting there), then I will create a new Triangle object. Generally when you create a new object, you capitalize it, but when you refer to the class, it is lowercase. So I will make a new Triangle object and declare the height to be 10 and the width to be 5.

    [–] ELI5: Web development: OOP PHP - Classes, Objects, etc. PUSSYDESTROYER-9000 1 points ago in explainlikeimfive

    Imagine spending hours creating some code that you can only use once. That would suck wouldn't it? If you wanted to make more complex programs you would have to code those complex programs from scratch.

    OOP or object oriented programming basically allows you to reuse code. For example I make some code for an object, let's say a vehicle. This vehicle object has a numWheels variable and a color variable. Now lets say I want to make a car object that is a subset of a vehicle object. With OOP, i can reuse the vehicle code and add some extra stuff specific to cars, such as numDoors or steeringWheelSide. OOP allows you to reuse simple stuff for more complicated stuff instead of making the complicated stuff from scratch.

    [–] What's the density of various types of nebula? PUSSYDESTROYER-9000 1 points ago in askastronomy

    Most nebulas have very similar densities, but planetary nebulas and supernova remnants have densities that vary with age since they are expanding clouds of gas that slowly diffuse through space.