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Kepler discoveries.

A bar graph of Kepler Discoveries. The vertical axis is labeled “Fraction Observed”, from 0 to .3, and the horizontal axis is labeled “Planet Size (Earth = 1)” from 0.5 – 0.7 to 16 – 23. A bar labeled “55” is above 0.5 – 0.7 Planet Size and approximately 0.03 Fraction Observed. A bar labeled “165” is above 0.7 – 1 Planet Size and approximately 0.07 Fraction Observed. A bar labeled “381” is above 1 – 1.4 Planet Size and approximately 0.165 Fraction Observed. A bar labeled “520” is above 1.4 – 2 Planet Size and approximately 0.23 Fraction Observed. A bar labeled “567” is above 2 – 2.8 Planet Size and approximately 0.26 Fraction Observed. A bar labeled “268” is above 2.8 – 4 Planet Size and approximately 0.12 Fraction Observed. A bar labeled “94” is above 4 – 5.7 Planet Size and approximately 0.04 Fraction Observed. A bar labeled “54” is above 5.7 – 8 Planet Size and approximately 0.025 Fraction Observed. A bar labeled “53” is above 8 – 11 Planet Size and approximately 0.025 Fraction Observed. A bar labeled “39” is above 11 – 16 Planet Size and approximately 0.02 Fraction Observed. A bar labeled “17” is above 16 – 23 Planet Size and approximately 0.01 Fraction Observed. At the top of the graph planets in our solar system are shown above their representative size as labeled on the x-axis. A gap between 1.4 – 2 and 2 – 2.8 is labeled “Sizes not seen in our solar system”.
This bar graph shows the number of planets of each size range found among the first 2213 Kepler planet discoveries. Sizes range from half the size of Earth to 20 times that of Earth. On the vertical axis, you can see the fraction that each size range makes up of the total. Note that planets that are between 1.4 and 4 times the size of Earth make up the largest fractions, yet this size range is not represented among the planets in our solar system. (credit: modification of work by NASA/Kepler mission)

What a remarkable discovery it is that the most common types of planets in the Galaxy are completely absent from our solar system and were unknown until Kepler’s survey. However, recall that really small planets were difficult for the Kepler instruments to find. So, to estimate the frequency of Earth-size exoplanets, we need to correct for this sampling bias. The result is the corrected size distribution shown in [link] . Notice that in this graph, we have also taken the step of showing not the number of Kepler detections but the average number of planets per star for solar-type stars (spectral types F, G, and K).

Size distribution of planets for stars similar to the sun.

A bar graph of Size Distribution of Planets for Stars Similar to the Sun. The vertical axis is labeled “Average Number of Planets per Star”, from 0 to .3, and the horizontal axis is labeled “Planet Size (Earth = 1)” from 1 – 1.4 to 16 – 23. A bar above 1 – 1.4 Planet Size rises to approximately 0.35 on the vertical axis. A bar above 1.4 – 2 Planet Size rises to approximately 0.27 on the vertical axis. A bar above 2 – 2.8 Planet Size rises to approximately 0.31 on the vertical axis. A bar above 2.8 – 4 Planet Size rises to approximately 0.14 on the vertical axis. A bar above 4 – 5.7 Planet Size rises to approximately 0.055 on the vertical axis. A bar above 5.7 – 8 Planet Size rises to approximately 0.048 on the vertical axis. A bar above 8 – 11 Planet Size rises to approximately 0.04 on the vertical axis. A bar above 11 – 16 Planet Size rises to approximately 0.01 on the vertical axis. A bar above 16 – 23 Planet Size rises to approximately 0.009 on the vertical axis. At the top of the graph planets in our solar system are shown above their representative size as labeled on the x-axis. A gap between 1.4 – 2 and 2 – 2.8 is labeled “Sizes not seen in our solar system”.
We show the average number of planets per star in each planet size range. (The average is less than one because some stars will have zero planets of that size range.) This distribution, corrected for biases in the Kepler data, shows that Earth-size planets may actually be the most common type of exoplanets. (credit: modification of work by NASA/Kepler mission)

We see that the most common planet sizes of are those with radii from 1 to 3 times that of Earth—what we have called “Earths” and “super-Earths.” Each group occurs in about one-third to one-quarter of stars. In other words, if we group these sizes together, we can conclude there is nearly one such planet per star! And remember, this census includes primarily planets with orbital periods less than 2 years. We do not yet know how many undiscovered planets might exist at larger distances from their star.

To estimate the number of Earth-size planets in our Galaxy, we need to remember that there are approximately 100 billion stars of spectral types F, G, and K. Therefore, we estimate that there are about 30 billion Earth-size planets in our Galaxy. If we include the super-Earths too, then there could be one hundred billion in the whole Galaxy. This idea—that planets of roughly Earth’s size are so numerous—is surely one of the most important discoveries of modern astronomy.

Planets with known densities

For several hundred exoplanets, we have been able to measure both the size of the planet from transit data and its mass from Doppler data, yielding an estimate of its density. Comparing the average density of exoplanets to the density of planets in our solar system helps us understand whether they are rocky or gaseous in nature. This has been particularly important for understanding the structure of the new categories of super-Earths and mini-Neptunes with masses between 3–10 times the mass of Earth. A key observation so far is that planets that are more than 10 times the mass of Earth have substantial gaseous envelopes (like Uranus and Neptune) whereas lower-mass planets are predominately rocky in nature (like the terrestrial planets).

Questions & Answers

this question is for atheists what created humans , how did they evolve
ilyes Reply
not entirely sure what this question has to do with Atheism but, firstly, there is no "who", life evolved in multiple paths, humans are simply one of those paths. The process of how life evolves is a very complicated but very well researched field of biology, so it would be worth doing research...
ben
...into that field, evolution isnt disputed. However, the direct path from the common ancestor (that we share with chimps) has not yet been completed. But know for sure that humans didn't just magically appear one day, it was over millions of years of evolution
ben
(I must ask though, what has this got to do with Atheism?)
ben
idk i thought believers will say god created us
ilyes
there are many types of believers one say that god created consciousness, one say we just magically appeared out of nowhere, and one say universe was created by God(all based on people I have met so far)
Tanmay
may i ask a question
Raluca Reply
yes why not you don't need to ask anyone for permission
Tanmay
-Why there are moons in every planet but there's note in mercure ?
Amal Reply
Well with mercury Venus also does not have moon.The reason that Mercury is not having moons is since it is too close to sun and thus if it would have any moon orbiting it ,then the moon will eventually attracted by sun due to it's high gravitational force whereas mercury has the lowest gravity
Anjali
The gravitational force of mercury is lowest in solar system and it won't be able to hold a moon in it's orbit
Anjali
Nice explanation
Asim
Thank you brother
Anjali
Did general theory of relativity leads us to singularity?
Asim
yes the general theory of relativity leads us to singularity
Anjali
But Einstein was not a believer of big bang. And singularity lead us to big bang?
Asim
yes Einstein was really astonished by his mathmatical answers that came fron his equations (this is what almost every one says)
Tanmay
and there are many theories stating how our universe came in which one is big bang
Tanmay
Einstein was against the fact that anything can come from nothing that our big bang says and he also thought that singularity (infinite mass in zero volume) can not be real(also what most people say)
Tanmay
also what most people say means that there is no evidence that he was against all these things
Tanmay
Okay
Asim
Tanmay
Asim
anything else
Tanmay
Do you believe that grand unified theory can be complete in future?
Asim
Do you believe that grand unified theory will be complete in future?
Asim
yes I do believe in it as I also believe big bang
Tanmay
Well i don't believe in big bang like Einstein didn't.
Asim
do you believe in wormholes are real?
Amit
@Asim then what do you think our universe came from or how it started
Tanmay
Well it's a myth.
Asim
@Amit I believe wormholes are real
Tanmay
It came from nothing Tanmay.
Asim
Even I believe in wormholes
Anjali
So Tanmay you must believe in baby universes.?
Asim
I believe that they are many things we can't explain or give prove but they are theories,imaginations and they are the basics for new discoveries
Anjali
So ,it is useless to argue over them
Anjali
But we should try to find new possibilities if we don't believe in old ones
Anjali
you are right @anjali
Amit
what is dark matter?
Amit
can a star turn into planet?
Amit
I have doubt on how Stephen hawking posses ideas of black hole by himself?
Enceladus
why do people believe in God and how are humans made
ilyes
No amit star can't turn into planet.
Asim
you are wrong asim
Amit
also Asim, please tell me why you think the big bang is a myth?
ben
@Asim what do you mean by it came from nothing what came from nothing
Tanmay
@Asik I don't know what baby universe is if you mean early universe then the question doesn't make sense
Tanmay
@Amit starts can become cold enough for us to live at high altitude but their surface will still be made of plasma
Tanmay
@Amit dark matter is a type of substance that doesn't interact with normal matter and also gives galaxies enough mass to hold its stars rather than to fly out by its rotation
Tanmay
Sorry Asim for wrong spelling of your name
Tanmay
@Tanmay thanks for your explanation
Amit
@Tanmay but a star can turn into a planet, but this transformation only happens for a very particular type of star known as a brown dwarf.
Amit
oh, somebody has google 😂
ben
I will check and then I will tell you if it's true or not thanks for the question
Tanmay
I will check as it is really wierd but thanks for your question
Tanmay
(oh no I was joking hahaha, Amit just took the definition that you see first on google and pasted)
ben
Tanmay baby universes is when something fell in black hole it's went into another universe called baby universe according to Stephen hawking. Well i don't know weather to believe it or not.
Asim
Amit brown dwarf are not planet or stars they have their own classification these are basically failed star, not massive enough to power hydrogen fission reaction.
Asim
ahh, didn't he use that to explain where "information" goes? because recently a paper was published stating that information may actually be re-emitted by the black hole as 'encoded' hawking radiation
ben
(so it may not be going to another universe, but instead coming back into our own)
ben
Hawking radiation are basically the the radiation emitted by black hole boundaries called event horizon.
Asim
@ben someone asked me this question today so i asked here and also google it..
Amit
So re-emitting doesn't make scene.
Asim
every black hole contains a singularity?
Amit
Yep absolutely.
Asim
ohhh, no worries dude, and yeah hawking radiation is a consequence of both quantum mechanics and relativity, really cool. And look it up Asim, it's a really interesting read
ben
but a singularity is a point in space where there is a mass with a infinte density. the problem is that infinities never exist in real world.
Amit
Ben it's really difficult to relate quantum mechanics to relativity.
Asim
Dude if you have done nobel price is waiting for you. (haha)
Asim
consequence of both quantum mechanics and relativity.!!!
Amit
Amit read theory of relativity and black hole singularities in Google. Everything will be cleared.
Asim
🤣🤣🤣
Amit
ok i will read this
Amit
hahahahaha, yeah that's true I'm being lazy as hell there haha, I mean more it's something relates the big and small (it's cool to see quantum phenomena having a direct effect on something predicted by relativity)
ben
(if a GUT is found I genuinely doubt I'd be able to comprehend the maths hahaha, maybe a long a way down the road but not yet)
ben
ben you are nominated for nobel as well as oscar for your thoughts..(hahaha)
Amit
what's you thinks about gravitational waves gentlemen?
Amit
hahahaha, and I love what I know so far but honestly dude, I've learnt essentially nothing about gravitational waves at university yet, I'm hoping that's going to be next year
ben
I would love to ask someone what the effects of constructive ans destructive interference of gravitational waves would be. Would total destructive interference lead to black holes?
ben
good luck for your next year... ben
Amit
if such things happen that's gonna be amazing.....
Amit
eyy thank you dude, likewise man, wish you all the best for your endeavours
ben
eyy cheers dude, likewise for you man, wishing all the best for you
ben
thanks buddy..
Amit
💝❤
Amit
(my bad, sometimes my phone wont show the first message as being sent, so I send another just in case)
ben
Gravitational Waves could help us travel faster in the space, if we are to set on an adventure like the one in The Interstellar, lol. Just saying
Awesh
what do u think created the universe
ilyes
m curious
ilyes
I believe in the theory where it states that our universe came from death of another universe and after our universe's death another universe will come from it
Tanmay
@Amit if that's what baby universe is then
Tanmay
my current understanding of universe and black holes, I would have to disbelief it
Tanmay
@Asim @Amit there is a feild in physics where we study about the physics of those objects who have intermediate size and follow some rules of quantum physics and relativity
Tanmay
@Ben what is full form of GUT?
Tanmay
@Ben I have never seen anyone spotting interference with gravitational waves but most of the people think that it will just be like interference in waves like light or sound. Do that means it's amplitude will change and will not create and black holes or stuff
Tanmay
@Awesh yes many people in youtube(some have good degrees and are astrophysicist) say that warping space is possible using gravitational waves
Tanmay
Do you all believe in multiverse
Anjali
I believe in multiverse
Tanmay
The relation between quantum physics and relativity is like sky and the land (hahaha)
Amit
what about the air between sky(let's assume height of clouds is sky) and land. It basically means that there is a field like that you should google it up
Tanmay
it's the most mysterious field and we almost know nothing about it. there are no laws(like Newton's law of motion) or something like that
Tanmay
The most undifined and fascinating theory is string theory what do u think about it?
Amit
what is the model about the earth being the center of the universe called?
Lordgy Reply
geocentric model
SCIENCE
I hope you got your answer.
SCIENCE
heliocentric universe
Jason
you are wrong Jason skerbinc
SCIENCE
in heliocentric model sun is at the center of the universe
Tanmay
what is black hole and stellar black hole
azeb Reply
does Millikan consider electron axial spin in his discovery of electrons mass using q/m ratio ? If No how it is possible that he found rest mass of electron (9×10^31 Kg) ?
Anurag Reply
how did light from up
Sourav Reply
Before there stars , there was matter and radiation . Before there were neutral atoms ,there was an ionized plasma ,and when that plasma froms neutral atoms , those allow the Universe to deliver the earliest light we see today .......
Apsara
how to know the distance of a star
Sourav Reply
What is time
Sourav
Technical Infinite Measurement of Evolution
Doc
not by the book but the simplicity of word play ....
Doc
to calculate the distance of a star we use parallax method (as far as my school has taught me).
Tanmay
in this method we see the star from one point and then after traveling some distance perpendicular to the distance of star we see it again. With this we can make a triangle and then it's median will give our distance
Tanmay
And time is just a way of defining when an event happened
Tanmay
oh and we will know the distance of all the 3 sides of triangle formed above if we multiply the time taken by light with speed of light and the third side will be known to us as it is dependent on our will
Tanmay
what are wormholes?
facty Reply
Holes made by worms
Neil
What is the difference between black hole and white hole ?
Apsara
black hole is the place where the massive body makes a large disturbance in space time fabric causing large gravity even light can't escape from it and all the bodies enter into on reaching a specific distance.
SCIENCE
A white hole is a hypothetical region of spacetime and singularity which cannot be entered from the outside, although energy-matter and light can escape from it. In this sense, it is the reverse of a black hole, which can be entered only from the outside and from which energy-matter and light can
SCIENCE
White holes appear in the theory of eternal black holes
SCIENCE
worm holes join 2 distant region of spacetime through which you can travel, covering large distance in short time
Tanmay
for example if you need to travel from A to B on a plane of paper then you can travel in a straight line joining those points but a worm hole will join those points using 3rd dimention which will make you travel that distance in short time
Tanmay
Hi,Do you known Kyaw Nyein Chan Hein!
zin Reply
No
Astrophysicist
Hello : I'm Kyaw Nyein Chan
zin
Hi I'm Kyaw Nyein Chan
zin Reply
Hello : good moring, I'm Kyaw Nyein Chan
zin Reply
hello good morning
Astrophysicist
good morning bro
Tanmay
how do you do?
Astrophysicist
I am fine what about you?
Tanmay
same as you
Astrophysicist
cool
Tanmay
How the Big Bang is made .
Apsara Reply
Kyaw Nyein Chan
zin
What is heliocentric
Apsara Reply
helio is from the greek god helios or ilios and means sun. Centric is from central. So heliocentric means with the sun in the middle
Robin
Usually in the context of astronomy its about the moment the world goes from the idea of 'earth in the middle of the solar system' to the idea that the sun is in the center of the solar system
Robin
so from a geocentric (geo meaning earth) to a heliocentric idea
Robin
yes correct this theory states that sun is in the middle of the solar system rather than earth
Tanmay
oh you have already said this
Tanmay
Hello: good afternoon
zin
hello
Tanmay
Thankyou to all to solve my doubt . I don't know more about the solar system beacause i am a small little girl my old is 9 and i love science but i am trying to learn more about science .
Apsara
that's great you should definitely check science in a nutshell YouTube channel it will provide you with good information
Tanmay
that's great you should definitely check science in a nutshell YouTube channel it will provide you with good information
Tanmay
that's great you should definitely check science in a nutshell YouTube channel it will provide you with good information
Tanmay
here is the link ***youtube.com/c/inanutshell
Tanmay
You not alone Apsara I'm 14 but know little about the universe
Swazi
what is solar system
Himanshi
what do you mean by astronomy
Himanshi
astronomy is a study of planetary science.
Enceladus
Astronomy is a branch of Physics that deals with the study of celestial bodies.
Satyam
An astronomy is a scientist in the field of astronomy who focuses their studies on a specific questions or field outside the scope of Earth 🌍🌎🌏 . They observe astronomical objects such as star's , planets , moon , comets and galaxies - in either observational (by analyzing the data)
Apsara
what is the difference between astronomy and cosmology
Astrophysicist
The collection of eight planets and their moon's in orbit around the Sun , together with smaller bodies in the form of asteroids , meteoroids and comets . The planet of the solar system are ( in order of distance from the sun ) Mercury , Venues , Earth ,Mass , Jupiter , Sartune ,Uranus , Neptune .
Apsara
In Astronomy, we study about celestial objects but in cosmology we study the origin and the formation of universe.
Satyam
how much temperature were can find on neptune
Ayyan Reply
the temperature is between -200 to -218 degree Celsius
Tanmay
Practice Key Terms 2

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Source:  OpenStax, Astronomy. OpenStax CNX. Apr 12, 2017 Download for free at http://cnx.org/content/col11992/1.13
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