Hi there, here comes a short introduction to this blog! The posts are divided in three categories. Regular posts, 'Just for fun' posts and 'The more you know' posts. 'The more you know' posts are for those of you, who would like to understand more about the physics of a subject, but they aren't necessary to understand the regular posts. There's also the 'just for fun' posts, just for fun!
Don't wanna be here? Send us removal request.
Statistics
We looked inside some of the posts by beautifulastronomybitches-blog and here's what we found interesting.
Average Info
Notes Per Post
1
Likes Per Post
1
Reblog Per Post
0
Reply Per Post
0
Time Between Posts
9 minutes ago
Number of Posts By Type
Text
17
Last Seen Tumblr Blogs
Fun Fact
Tumblr Inc. is using 66 technologies for its website.
Text
Is Tatooine Out There?
Tatooine as seen in Star Wars: A New Hope, 1977, Lucasfilm - Source
Kepler-16b is a circumbinary planet, meaning it orbits two stars, in this case the binary stars Kepler-16A and Kepler-16B. So if you stood on Kepler-16b, you would see two suns. Does that remind you of anywhere? Yep, this is real life Tatooine, the home planet of Luke and Anakin Skywalker. While Tatooine is a very hot desert planet underneath two scorching suns, Kepler-16b is a cold, hostile planet with a gaseous surface and the two stars are both smaller than our Sun.
Other real life Star Wars planets include OGLE-2005-BLG-390Lb, affectionately nicknamed Hoth by NASA and CoRoT-7b, that resembles Mustafar, the volcanic planet, where Obi-Wan Kenobi and Anakin Skywalker had their duel.
And of course, Mimas, a moon of Saturn, and in this case, how about we just leave this picture here.
Mimas captured by spacecraft Cassini - Source
Sources: Wookiepedia - Tatooine, NASA - Kepler-16b, SPACE - 10 Real Alien Worlds That...
0 notes
Text
The Search for Life
We look for planets, that looks like the Earth in hope of finding life elsewhere in the Universe. These planets has to lie in the Goldilocks zone, where it’s not too cold and not too hot, but just right. In this case ‘just right’ means 0-100 degrees celsius, the temperature for there to be fluid water on the surface. A colder star would have the habitable zone closer than a warmer star. Besides this, the planet must fulfill other requirements, such as having an atmosphere for breathable air and to hold the warmth from its star in, the star it orbits being stable and the planet should have a certain mass for it to have a gravity that can hold the atmosphere.
Artist concept of Kepler-452b - Source
In the search of terrestrial planets, the Kepler telescope and K2 has been used and together they’ve found more than 2000 confirmed exoplanets and 5000 candidates for exoplanets. One of the most (if not the most) Earth-like planet found is Kepler-452b. It orbits the star Kepler-452 about 1400 light years away. It has an estimated mass of 5 times the mass of the Earth and a radius of 1.5 Earth radii. Kepler-452b was found via the transit method and has a period of 385 days, almost an Earth-year.
Artist concept of Proxima Centauri b - Source
The closest exoplanet is Proxima Centauri b, orbiting our closest star Proxima Centauri, 4.2 light years away. It’s practically the same size as Earth, but it might be tidally locked. Tidally locked means it’s always facing the same way, like we always see the same side of the Moon. This would mean it’s always hot and day on one side of the planet, and always cold and night on the other. Proxima Centauri b was found with the radial velocity method.
Sources: Wikipedia - Kepler-452-b, Wikipedia - Proxima Centauri b, scienceabc - What Makes a Planet Habitable?
0 notes
Text
Just For Fun - Mother Sun
1 note
·
View note
Text
The More You Know - Gravity & Relativity
This part is going to be a little bit tricky - we’re going to talk about Einstein and gravity. Theories of gravity start all the way back with Galilleo Galilei in the early 1600′s. He proposed that if you dropped two objects of different mass from the same height, they would hit the ground at the same time - that their gravitational acceleration would be the same. Had he actually done this, he might have been in trouble; things like air-resistence would have been in the way, but otherwise he was right: Two object will have the same gravitational acceleration, only depending on where in the gravitational field they are, and not on their mass.
Then came Newton in the late 1600′s, and found an equation for the gravitational force between two objects. It’s between two objects and not just one object on the other, as he stated in his third law: For every force excerted on a body, there must be an equally sized object in the opposite direction. With this equation, Neptune could be predicted. Uranus’ was being pulled, and not only by the already known planets: There must be something more, and that was Neptune pulling.
Newton’s theory wasn’t perfect. Something was wrong with Mercury; its orbit changed. The point closest to the Sun, perihelion, wasn’t in the same place everytime, it moved a little every orbit, and Newton’s theory couldn’t explain this. Cue Einstein and the theories of relativity. Einstein came up with two theories, the special theory and the general theory. Special relativity came first and is based on two postulates:
1. The laws of physics are the same in all inertial systems.
2. The speed of light is the same for all observers in all systems.
Unfortunately, special relativity is not very good when it comes to acceleration, and so general relativity, GR, was necessary. GR starts with the equivalence principle, which states that an observer cannot distinguish between acceleration and a gravitational force, if they cannot see outside. Now there’s a connection between acceleration and gravity, and since acceleration is length per time squared, there’s a connection between space, time and gravity. GR describes space and time as one thing, spacetime, and it’s often called the fabric of spacetime. Now, this is actually a four-dimensional thing, so please do yourself a favour and don’t try and imagine this. You can’t. Instead, imagine a, well, piece of fabric. A heavy object will weigh down the fabric more than a light object.
The fabric of spacetime with objects weighing it down. - Source
GR could be used to explain why Mercury acted the way it does. The curves the Sun causes in spacetime, would cause Mercury’s orbit to change a little bit. The calculation of how much this change would be, happened to fit with the actual measurement of Mercury’s orbit. A win for GR.
Mercury’s orbit with its changing perihelion. - Source: Foundations of Astronomy
Sources: Wikipedia - Gravity, Foundations of Astronomy by Dana Backman and Michael Seeds
0 notes
Text
Gravitational Microlensing
The light from the background star through the front star and its planet. - Source
Gravitational microlensing is an effect like the one you see, when you use a magnifying glass to focus the light of the Sun to start a fire. For this method, you need a star right behind another one. As the front star passes in front of the background star, its gravity will focus the light and we’ll see the light coming from this point at rising and then falling again. Now, if the front star has a planet close by, that planets gravity will do the same thing to the light and cause an extra blink of light for a short while.
How we’ll see the light. The planet causes an extra blink. - Source
Unlike some of the other methods, this method can be used to find planets very far away from the Earth, but unfortunately they’re much more randomly seen.
Sources: NASA - 5 Ways to Find a Planet, Planetary Society - Microlensing
0 notes
Text
Direct Imaging
The light from the star is blocked out and you can see the planet.
Direct imaging is, as the name suggest, to look at the planet directly. Of course, this is difficult to do, as the stars the planets orbit tend to outshine them by quite a lot. You’re going to have to block out the light from the star. Two ways to do this is with a coronagraph, - a device inside of the telescope, that blocks out the light, creating a fake eclipse of sorts - and a starshade, - a device outside of the telescope, that blocks out the light before it even hits the telescope.
Source: NASA - 5 Ways to Find a Planet
0 notes
Text
Astrometry
In astrometry, you see the star move as it orbits the center of mass.
Astrometry is another way than the radial velocity method to see the star move around, except in this way you measure on the actual movement of the star. This is extremely difficult to do as the stars move so little and on top of this the Earth’s atmosphere bends and distorts the light from the star. Astrometry is easiest to use on nearby objects, because looking a tiny movement over a large distance is almost impossible.
Source: NASA - 5 Ways to Find a Planet
0 notes
Text
Transit
Animation showing how the light dips as the planet moves in front of the star. - Source
Transit is a solar eclipse happening on a faraway star. We notice the light from a star dipping for a little while and then rising again. This is when a planet passes in front of the star and blocks some of the light. As with the radial velocity-method, you have to see this pretty straight on, otherwise there won’t be any eclipsing at all. This method can tell us a lot about the planet: The radius of the planet can be calculated from the amount of light it blocks, how far away from the star it is can be found from how long it takes to pass the star, the velocity of the planet with it’s period and if the planet has an atmosphere, the light passing through it, might tell us something about it’s composition.
Like the Earth, some stars have more planets, and different planets would have different periods and different sizes, and this would of course make the amount of light blocked different all depending on which planet or if more planets passed in front of the star. A larger planet would block more light, and were both planets to be in front of the star at the same time, they would both block light depending on their size. It makes it more difficult of course, but it’s not impossible to pick apart the data and learn about the different planets.
Source: NASA - 5 Ways to Find a Planet
0 notes
Text
The More You Know - The Doppler Effect
Let me pull out a classic example of the Doppler effect - an ambulance is driving towards you with its sirens on. As it drives right past you, the sound changes; it becomes lower. You are experiencing the Doppler effect, or the Doppler shift.
(a) shows the waves emitted from a stationary object - when the ambulance holds still. (b) shows the waves from an object moving to the left. You’re standing to the left of the circles as the ambulance moves towards you and then to the right as it moves away from you.
Sound - like the siren - comes in waves, spreading from its point of origin outwards. These waves come towards you with the speed of sound (343 m/s at room temperature), and has a certain wavelength and therefore a certain frequency. But when the ambulance moves towards you, the waves are sent out closer to each other, than if the ambulance stood still, and the waves become shorter. When the waves become shorter, the frequency becomes higher and you will hear a higher tone. When the ambulance passes you, it starts moving away from you and the waves are sent out further and further apart, making the waves longer, the frequency shorter and the sound you hear lower.
The light spectrum. The visible light is between 380 and 780 nm, with red having a longer wavelength than blue. - Source
Light happens to move in waves* as well and can also be Doppler shifted. When the wavelength of light is changed, it changes colour. So when a star moves away from us, it’ll appear redder than a star moving closer to us. As the Universe expands, most objects in the sky will appear to be moving away from us, but a few, like our closest galaxy, Andromeda, moves toward us.
The connection between the velocity of the object and the change in wavelength is:
Where V_r is the radial velocity of the object (the velocity it has straight away from us), c is the speed of light, lambda is the wavelength, that can be measured in a laboratory and delta-lambda is the change in wavelength, meaning the wavelength you actually measure from the object minus the laboratory value. If the change in wavelength is positive, the velocity will be positive and the star will be moving away from you. The change in velocity is positive, when the measures wavelength is bigger than the laboratory value - and this fits with a redshift.
Source: Foundations of Astronomy by Michael Seeds and Dana Backman
*Light is very strange and is both waves and particles at the same time. If you’re more curious about light here’s a short video by Colm Kelleher.
0 notes
Text
Radial Velocity
When you look at a star and planet system, you’ll usually see the planet orbiting the star, but actually they orbit each other. The center of which they both orbit is just usually inside the star, so it’s hard to see the star move at all. But it’s this movement we see, and if the star’s moving, - or ‘wobbling’ - something must be pulling it - a planet. Sometimes the radial velocity method is called the ‘wobble-method’.
But how do we see this movement at all, when it’s apparently so difficult to spot? It’s due to the Doppler effect, and as the star turns in a circle around itself, it will be moving away from us some of the time and closer to us some of the time. As it moves away, the light waves will be stretched and they’ll appear redder. This is called redshift. When the star moves closer to us, the waves will be squeezed tighter and they’ll look bluer. (Occasionally, this is called blueshift, but it’s not necessary - it’s just a negative redshift.) You usually can’t see the actual change in colour in the star, but it’s measurable. When this method is used, an estimate of the planet’s mass can be given.
Wavelengths become shorter and therefore bluer as a star moves toward us - and longer and redder as it moves away.
The radial velocity method is only working when the we see the planet orbit the star straight on, otherwise the star wouldn’t be moving away from and to us, but in a circle and then there wouldn’t be a redshift. If we see it at an angle, the estimate of the planet’s mass will be slightly off as well. It works best with large planets close to the star, as they have the biggest effect on the star.
The easiest planets to detect with this method are ‘hot Jupiters’, which are planets very similar to Jupiter, - a gas giant. They are very close to their star and has a short period, making them ideal to look for with the radial velocity-method.
Source: NASA - 5 Ways to Find a Planet, Wikipedia - Hot Jupiter
0 notes
Text
Outside the Solar System
When the sky is clear, and the darkness has fallen, go outside and look up. You’ll see the sky littered with tiny speckles of light. Stars. Thousands of them. And those are only the ones visible to the naked eye on a dark night. In fact, there’re billion of stars just in our galaxy, and billions of galaxies, and that makes billion trillions of stars. It wouldn’t be far off to assume some of these stars have planets; there are 8 just in our Solar System. A planet that orbit another star is called an exoplanet. Look up again. See those tiny speckles up there. Now remember how small the Earth is compared to the Sun. (We’ve shown you!). Now connect those dots: Exoplanets must be really small and really hard to see.
Luckily there’s a few ways to detect these. Five of these methods are: transit, radial velocity, direct imaging, astrometry and gravitational microlensing. They’ll be explored a bit more in depth in the next few posts.
Graph plotting known exoplanets with size and orbital period on the axises. - Source
Most of the planets we’ve found are planets with short periods and a large mass close to their stars. Larger planets closer to their stars are easier to find, as they affect their stars more than smaller. We’ve also found more planets with shorter periods, as they come around their planet more often, and as a we have to see three orbits before we can confirm it as a planet, these are confirmed much faster.
Source: Sky and Telescope - How Many Stars Are There?
0 notes
Text
Let’s Take a Walk Through the Solar System
youtube
0 notes
Text
Space Rocks
There’s a lot of other, smaller stuff than planets and dwarf planets in the Solar System, collectively called small Solar System bodies.
First we have asteroids. Asteroids are small space rocks orbiting the Sun. They’re often oddly shaped, as they’re not large enough to have enough gravity to pull them into a sphere. Most of them orbi the Sun in the asteroid belt between Mars and Jupiter. The reason there is an asteroid belt here, is from when the Solar System formed and the dust and particles in the disc around what would become the Sun formed planets. The space between Mars and Jupiter didn’t do that. It just stayed a belt of rocks. The biggest object in the asteroid belt is the dwarf planet Ceres.
There’s actually another asteroid belt in the Solar System: The Kuiper Belt. It’s outside of Neptune’s orbit, and is believed to have formed in the same way as the asteroid belt, but it’s not sure. There’s also the theoretical Oort-cloud even further away, but it is theoretical. It’s a sphere around the entire Solar System, unlike the asteroid belts, which are just discs.
Then we have meteors, meteoroid and meteorites. These are actually all the same thing. A meteroid is a small object moving in space, often a piece from a collision between two asteroids. If it enters the Earth’s atmosphere and you can see it in the sky, it becomes a meteor (or commonly called a shooting star.) If it’s large enough to not just burn up in the atmosphere, then the remaints, that hits the Earth, is called a meteorite.
Halley’s Comet, March 8, 1986. - Source
We also have comets. Comets orbit the Sun like asteroids do, but contains more ice and gas, and when they venture close to the Sun, ice vaporises and can create a tail, like the meteors. Unlike the meteors, comets can be seen when they are far away. A wellknown comet is Halley’s comet, that has a period of 75 years. It comes around Earth again in the year 2061.
Source: NASA - Asteroid or Meteor?, Wikipedia - Halley’s Comet, Foundations of Astronomy by Dana Backman and Michael Seeds
0 notes
Text
Neptune - Last And Definitely Least
Neptune - Source
Radius: 24.622 km
Mass: 1,02*10^26 kg
Distance from the Sun: 4,49*10^9
And finally the last (actual) planet in the Solar System, Neptune. We don’t actually know that much about Neptune. But because of discoveries of exoplanets that are very similar to Neptune in size and colour, astronomers have a newfound interest in the planet. Even though Neptune is heavier than Uranus, it has a bigger density, and is smaller.
We actually kind of know more about Neptune’s moon Triton, which is the largest moon to orbit Neptune. Triton is pretty strange. Its orbit is angled so it doesn’t lie in the same plane as the other moons, and besides that its rotation is retrograde to Neptune’s and the other moons’ rotations. Also Saturn, Jupiter and Uranus have moons that does this, but the biggest of these (Saturn’s moon Phoebe) only has a size that is about 8% that of Triton. These observations has made astronomers believe that Triton didn’t form around Neptune, but was captured by its gravity. Another thing about Triton is that when Voyager 2 passed it, it was discovered that the moon has active geysers, and is otherwise geologically active, despite its small size (2/3 the size of our moon). This can be explained if Triton once had a very eccentric orbit, where tidal forces pulled the moon in to a less eccentric one. These tidal forces could continue to heat up the moon, to keep Triton geologically active.
Source: En lille bog om universet by Anja C. Andersen, Backyard guide to the night sky by Howard Schneider, Foundations of astronomy by Dana Backman & Maichael Seeds
0 notes
Text
Uranus - The Tired One
Uranus - Source
Radius: 25.362
Mass: 8,68*10^25 kg
Distance from the Sun: 2,87*10^9 km
In the original Solar System, there were six planets: Mercury, Venus, Earth, Mars, Jupiter and Saturn; the planets you can see with the naked eye. The reason is obviously because the telescope wasn’t invented yet, but still som time passed between the invention of the telescope, and the discovery of Uranus. Even though Galilei came close to discovering the planet for himself, he marked it down as a star. It wasn’t until 1781 where the German composer and astronomer William Herschel noticed that the star was moving. Because of disagreements over the name (Herschel wanted to name it Georgium Sidus, or George’s Star after the king) the planet wasn’t named until 1850, four years after the discovery of Neptune.
Because of the astounding distance to Uranus not much is known about the planet. Only Voyager 2 has laid its path past the planet, capturing the first ever quality picture of the planet in 1986.
A very strange thing about Uranus, is that its axis is tilted 98 degrees, so the planet is laying down. This also means that during Uranus’ 84 year orbit that the poles are in constant light then constant darkness for 42 years at a time. something even stranger is that the warmest place on Uranus is still at the equator. It is still unknown why Uranus’ axis is tilted that much, but it is possible that Uranus collided with an Earth-sized planet in its early years.
Source: En lille bog om universet by Anja C. Andersen, Backyard guide to the night sky by Howard Schneider, Foundations of astronomy by Dana Backman & Maichael Seeds
0 notes
Text
The More You Know - The Gaps in Saturn’s Rings
You might have noticed how Saturn’s rings aren’t a solid thing, but actually have gaps in between them. This can be explained by Saturn’s moons.
First of all it is important to understand that the rings orbit around Saturn, but their speeds are different from one another. This can also be seen as the planets’ speed around the Sun in their respective orbits are different. Long story short, the closer an object is to the object it is orbiting, the faster the orbit.
The moons also has an orbital speed, or an orbit period, which is the time it takes for the moon to move around Saturn once. Somewhere between the moon and Saturn there will be an orbit (no matter if there actually are an object in that precise orbit), which has a period half that of the moon. This means that if an object has that particular orbit, it will be at the same spot in its orbit every time the moon is next to it, and this of course happens every other time for the object. Because of the gravity between the two objects, the moon will slowly pull the object out of course, making its orbit more and more eccentric. Because many of the moons’ orbits are bigger than the rings, some of these other orbits lie inside of the rings. That means that when an orbit gets more eccentric it is pulled out between other objects and sort of lays to rest there, leaving a gap where its old orbit was.
0 notes
Text
Saturn - The Beauty of the Solar System
Saturn - Source
Radius: 58.232 km
Mass: 5,68*10^26 kg
Distance from the Sun: 886,5*10^6
The first thing you think about when Saturn is mentioned, is of course the beautiful rings that surround its center. It was Galileo Galilei who first observed the rings as two bulges on either side of Saturn, that would first disappear and then later show up again as an ellipse. Galilei made notations of these observations, but never figured out why he saw what he saw. It was only 40 years later that Christiaan Huygens found the explanation. What Galilei had seen was the rings, but because of Saturn’s axis’ tilt, we see the rings from different angles as Saturn move around its orbit. When it ‘disappeared’ from Galilei’s view, the rings must have been angled directly at Earth, which happens about every 15 years.
One would think that Saturn’s rings are one of a kind, at least in our solar system, but there are actually rings around all of the gas giants. The reason why Saturn’s rings are so easily viewed in comparison, is because of the amount of ice in the rings, that reflect the light from the Sun better than the rocks and dust that the rings also consists of. The pieces in the rings range in size from about 1 centimeter to 10 meters. The total thickness of the rings aren’t thicker than a few kilometers many places, and the thickest places they are only 700 kilometers (again that’s not very much considering the scale of things here).
Other than the rings, Saturn also has quite a few moons, and still more are discovered to this day, right now the number lies (around) 53. The biggest moon Titan is first and bigger than Mercury, and also stands out by having a pretty dense atmosphere. The moon has a pretty thick cloud cover, so we didn’t know what the surface looked like before we sent a probe, called Huygens, down to the surface. The moon’s surface looks surprisingly much like the surface of the Earth, because of liquid Methane that act like the water here on Earth. There is also water on the moon, but only in ice form since the temperature on Titan is about -179 degrees Celcius.
Source: En lille bog om universet by Anja C. Andersen, Backyard guide to the night sky by Howard Schneider, Foundations of astronomy by Dana Backman & Maichael Seeds
0 notes