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Gravitational Waves

Advanced LIGO: https://www.advancedligo.mit.edu. The full story on this gravitational wave observatory.

eLISA: https://www.elisascience.org.

Gravitational Waves Detected, Confirming Einstein’s Theory: http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html. New York Times article and videos on the discovery of gravitational waves.

Gravitational Waves Discovered from Colliding Black Holes: http://www.scientificamerican.com/article/gravitational-waves-discovered-from-colliding-black-holes1. Scientific American coverage of the discovery of gravitational waves (note the additional materials available in the menu at the right).

LIGO Caltech: https://www.ligo.caltech.edu.

Videos

Black Holes

Black Holes: The End of Time or a New Beginning?: https://www.youtube.com/watch?v=mgtJRsdKe6Q. 2012 Silicon Valley Astronomy Lecture by Roger Blandford (1:29:52).

Death by Black Hole: http://www.openculture.com/2009/02/death_by_black_hole_and_its_kind_of_funny.htm. Neil deGrasse Tyson explains spaghettification with only his hands (5:34).

Hearts of Darkness: Black Holes in Space: https://www.youtube.com/watch?v=4tiAOldypLk. 2010 Silicon Valley Astronomy Lecture by Alex Filippenko (1:56:11).

Gravitational Waves

Journey of a Gravitational Wave: https://www.youtube.com/watch?v=FlDtXIBrAYE. Introduction from LIGO Caltech (2:55).

LIGO’s First Detection of Gravitational Waves: https://www.youtube.com/watch?v=gw-i_VKd6Wo. Explanation and animations from PBS Digital Studio (9:31).

Two Black Holes Merge into One: https://www.youtube.com/watch?v=I_88S8DWbcU. Simulation from LIGO Caltech (0:35).

What the Discovery of Gravitational Waves Means: https://www.youtube.com/watch?v=jMVAgCPYYHY. TED Talk by Allan Adams (10:58).

Collaborative group activities

  1. A computer science major takes an astronomy course like the one you are taking and becomes fascinated with black holes. Later in life, he founds his own internet company and becomes very wealthy when it goes public. He sets up a foundation to support the search for black holes in our Galaxy. Your group is the allocation committee of this foundation. How would you distribute money each year to increase the chances that more black holes will be found?
  2. Suppose for a minute that stars evolve without losing any mass at any stage of their lives. Your group is given a list of binary star systems. Each binary contains one main-sequence star and one invisible companion. The spectral types of the main-sequence stars range from spectral type O to M. Your job is to determine whether any of the invisible companions might be black holes. Which ones are worth observing? Why? (Hint: Remember that in a binary star system, the two stars form at the same time, but the pace of their evolution depends on the mass of each star.)
  3. You live in the far future, and the members of your group have been convicted (falsely) of high treason. The method of execution is to send everyone into a black hole, but you get to pick which one. Since you are doomed to die, you would at least like to see what the inside of a black hole is like—even if you can’t tell anyone outside about it. Would you choose a black hole with a mass equal to that of Jupiter or one with a mass equal to that of an entire galaxy? Why? What would happen to you as you approached the event horizon in each case? (Hint: Consider the difference in force on your feet and your head as you cross over the event horizon.)
  4. General relativity is one of the areas of modern astrophysics where we can clearly see the frontiers of human knowledge. We have begun to learn about black holes and warped spacetime recently and are humbled by how much we still don’t know. Research in this field is supported mostly by grants from government agencies. Have your group discuss what reasons there are for our tax dollars to support such “far out” (seemingly impractical) work. Can you make a list of “far out” areas of research in past centuries that later led to practical applications? What if general relativity does not have many practical applications? Do you think a small part of society’s funds should still go to exploring theories about the nature of space and time?
  5. Once you all have read this chapter, work with your group to come up with a plot for a science fiction story that uses the properties of black holes.
  6. Black holes seem to be fascinating not just to astronomers but to the public, and they have become part of popular culture. Searching online, have group members research examples of black holes in music, advertising, cartoons, and the movies, and then make a presentation to share the examples you found with the whole class.
  7. As mentioned in the Gravity and Time Machines feature box in this chapter, the film Interstellar has a lot of black hole science in its plot and scenery. That’s because astrophysicist Kip Thorne at Caltech had a big hand in writing the initial treatment for the movie, and later producing it. Get your group members together (be sure you have popcorn) for a viewing of the movie and then try to use your knowledge of black holes from this chapter to explain the plot. (Note that the film also uses the concept of a wormhole, which we don’t discuss in this chapter. A wormhole is a theoretically possible way to use a large, spinning black hole to find a way to travel from one place in the universe to another without having to go through regular spacetime to get there.)

Questions & Answers

Why no object can travel with speed greater than light?
geometry Reply
what is Deja Vu theory?
rockstar Reply
Have you ever felt like something has ever happened before? That's Deja Vu. The Deja Vu theory says that once you have those visions, you are actually experiencing what an alternate reality would have been. Basically it's the collision of both our universe and another.
AlteredEdge
Yeah it gives us an idea about the existence of a parallel universe
Debabrata
is this a hypothesis? or theory? isn't there something with your brain/memory processing the image or info twice in a few seconds?
Collins
I do also love this experience, seems so unreal but real all at once.
Collins
this can be real if we will solve the mystery of quantum physics .
YOG
I was giving just giving my own hypothesis of the general topic. While it would be interesting to find that we transitioned through dimensions, I think it just boils down to a heightened ability to predict future outcomes and a series of subconscious decisions to enact one of those possible outcomes
AlteredEdge
What I'm saying is that it's all in your head. 😂
AlteredEdge
yeah its all in our heads for sure, the brain is amazing, all of the above hypothesis really interesting. one day hopefully we might figure it out.
Collins
I hope that this hypothesis might be proved true
Debabrata
I feel deja vu is kind of a wormhole which connects us to a parallel universe.
geometry
I like what you said 'alterededge' "dena vu" is a vision of a past memory reenacting itself at an unexpected time and place. traveling and transitioning through dimensions.
Alba
opps, "deja vu"***
Alba
you are are right Geometry Lover.
Alba
Deja vu might even prove the existence of future time travel.
geometry
Well I'm not exactly saying it's a memory, it still hasn't happened yet, more like subconscious pre-cognitive thinking, where your mind eventually leads you down a path that makes the "deja vu" experience reality true after you had it.
AlteredEdge
We says time as a 3rd dimension and space as a fourth dim, so as come to 5 dimension what we say? I hope you got my point
Asim
According to string theory there are 10 dimensions
Debabrata
Yes you are right Mishra
Asim
But Tesseract is said to be 5 dim
Asim
How?
Asim
How do giants planets remain gaseous when they are located in cold regions of the solar system? Do they generate enough heat and if they do, are they not able to also heat their moons?
Kuda
Kuda just to answer part of your question. The gas inside Saturn for example is extremely dense not like gas in a room. The definition of gas is that the particles have little to no interaction between each other meaning there's no chemical bonds.
Sandra
hello ,what kind of question is that?
Bata Reply
what is weather
Susil Reply
Hey guys, question. It is said that Uranus' famous axial tilt of 98 degrees was caused by collisions billions of years ago. How can a celestial body/object 'collide' with a body (Uranus) which is made up of gas and has no surface?
Joey Reply
Although Uranus has no phyiscal surface, it still has a core. It's possible that in the early stages of the solar system, a rouge planet or moon tore through the upper levels of the atmosphere and was able to penetrate the lower cloud levels and eventually reach gas giant's core.
AlteredEdge
are there aliens in the universe?
Lesego Reply
might be possible but there is no true evidence of it.we can only assume because we don't know the exact size of universe,it's infinite,so possibilities always shown is in infinite.
Near
might be possible because UFO's are being seen on earth
Vinay
is also a little ridiculous
Tracy
I feel I need to confess the only life the universe created for us to see and feel is the one in human form on Earth. its possible we make ourselves sick straining our thoughts to think of connecting with human life on or in any other realm other than the one we are in.
Alba
goodnight, I will continue our conversation tomorrow.
Alba
there was nothing created for anyone, its literally just there, there is no reason, it just is, don't be dumb
Tracy
We Are Not Special, We Just Happen To Be The Species That Evolution Has Shaped So Far.....
Adam
If the universe is limitless, life could be limitless as well. According to science and mathematics of course!
stijn
how?
Emilya
The universe is so vast and complicated it's impossible to ever rule out the possibility of intelligent life, but the gradual realization by human society is that we are not "special" in any given way. I recommend everyone here watch Issac Arthur on Youtube, he takes a look into the Fermi Paradox.
AlteredEdge
Thank You AlteredEdge, I Will Check It Out.....
Adam
Adam i have a question
Asim
Why does traveling at close to light speed or being near super dense objects cause time to dilate?
Andrew Reply
good question. time is only what we made it. the way light travels with and without gravity has always been a wonder to me.
Collins
What do you mean without gravity?
Andrew
I'm actually not sure, this might be a silly question but does gravity effect light in respect to time?
Collins
As you move faster the slower the time
Asim
yes , gravity can effect light you can take example of black holes .
YOG
yes this makes sense, so do we know what kindo of effect it has on time around a black hole?
Collins
Since a black hole has an extreme amount of mass compacted into such a tight density, it warps space and time around it. Why? The main reason is gravity. It is always the dominant factor in black holes. Light in this case is absorbed like everything else.
AlteredEdge
Time in a black hole is slowed down compared to outside the black hole, this again is caused by gravity. Same principle works on Earth.
AlteredEdge
but black holes only bends space-time febric and light didn't change its path it always travel in straight line but the space febric is curved so it looks like that light bend or obserbed by black holes.
YOG
Black Holes do bend the fabric of space-time, but light is no exception. Light is matter just like everything else.
AlteredEdge
this is great info/convo. without a black hole, does gravity effect light in any other way,? like the way water bends light. just curious if the knowledge is there, any site recommendations for research, would be greatly appreciated.
Collins
So like your saying, outside of the extreme of a black hole, light travels in a straight line. However when it comes in contact with a large mass (lets say the sun) it curves space around it. So from an outward appearance the light bends to the gravity which causes what we call gravitational lensing
AlteredEdge
yes exactly, ok wow yes that makes alot of sense, thank you very much for this info/feedback, gravity seems like the top of the food chain in the universe, trying to find out, for my own research, how much we know about it to date and its affect on other objects/masses etc. thanks again
Collins
Of course! Also to help you out incase you didn't already know, but gravity travels in waves and varies in strength.
AlteredEdge
wow ok I did not know that either, thank you,. slightly like the way sound travels maybe? other info I will be glad to hear if your sharing, thanks again AlteredEdge
Collins
what is the definitions of planet
Mitrajit Reply
A celestial body orbiting around a star
Asim
How to appear for MCQ in this app
nitisha Reply
I l don't understand questions
Nkateko Reply
which quesrions?
Ankit
let it be
nitisha
How to make a telescope
Amit Reply
***youtube.com/channel/UClBN_RpR5X8IdrARwnaL3fg
Steve
***wikihow.com/Make-a-Telescope
Jennifer
optical mechanics
Astro
aptical
Nkateko
Why the God make universal ?
Trung
because God itself don't know.
Near
Which one has the ring
Isaac Reply
Saturn venue and even Jupiter all have rings the rings on Jupiter, however, aren't so easily noticed due to them only being viable through infrared
Hunter
visible *
Hunter
they each have three rings but not as you might think just think of them all as one big ring because that's basically what they are but they are desperate individual rings
Hunter
separate*
Hunter
can you tell me what is a quantam elighment? Lets see how many people give write answers
gdjm Reply
can you tell me what is a fomalhaut?
gdjm
Fomalhaut Is The Brightest Star In The Constalellation Of Piscis Austrinus.....
Adam
joe.
Tracy
Do You Mean Quantum Entanglement?
Adam
yes
gdjm
No Adam fomalhaut mean eye of universe
gdjm
quantum entanglement is when a husband has been married so long to his wife that he is directly influenced by her action usually in an opposite way. 🤣
Jocofranc
It Is Also The Brightest Star Of The The Constalellation Of Piscis Austrinus.....
Adam
who was the first person to get to the planet
Isaac
Is 5 dimensional exists
Asim
Hello
Asim
Hi, have u read about the many dimensions we possibly have? it's more than 5.
Collins
there are 11 dimensions acc. to the M theory, 10 acc. to string theory and 26 acc. to bosonic theory. but we basically follow the M theory ..
BHUMI
thanks for clearing that up.
Collins
Adam
Asim
can anyone tell me daily rotation of the sun in tokyo
Liridona Reply
tokyo has it's own personal sun
Tracy
can you send me any pictures of the tokyo sun
Liridona
sure! ig?
Tracy
here can u?
Liridona
no it wont let me sadly
Tracy
or
Liridona
snapchat
Liridona
i dont have snapchat 😰
Tracy
okay ig
Liridona
my ig is fatwigga37 if you'd like to see :)
Tracy
Can we use SI units in the equation of Kepler's third law?
Naiyu Reply
can u tell the equation pls
sasmita
how does religion enters to this topic when god created this world
Sakira
How Do You Know A God Created Our Planet?
Adam
you must read bible
Sakira
u must the bible
Sakira
How Do You That Book Is Authentic? And I Have Read The Bible, The Koran, The Torah And The Urantia.....
Adam
The law is T^2 is proportional to R^3 where t is planet's time period and r is average of semi major axis and semi minor axis. Also,don't turn this place into a religious warzone. We already have idiots fighting about religion.
priyanshu
If I Had A Book That Said Insects Created The Universe, Would That Make It Fact?
Adam
Have You Ever Heard Of The Council Of Nicaea?
Adam
Through Out History Mankind Has Worshipped Over 5000 Different Gods, How Do You Know Christ Is The True God?
Adam
God Is A Hypothesis..... The Definition Of Faith Is Belief Without Proof.....
Adam
Thank You Prianshu Roy, This Is A Forum For Science Not Archaic Stories Written By Sheep Herders, Well Said.....
Adam
Hebrew 13:1
onome
P2 = a3
Adam
So You Quote A Bible Verse, Now What?
Adam
Science Discourse Nothing Else.....
Adam
god is real he's not just a wise guess
Sakira
god bless you
Sakira
u know what,u are not here if god werent there!
Sakira
Science Discourse, Nothing Else.....
Adam
Thier Are Many Religious Sites You Can Go To, To Discuss God.....
Adam
hahahaha
Sakira
Have A Great Day.....
Adam
night time here
Sakira
Look Up The Definition Of Day, Instead Of Trying To Look Witty, Again Have A Great Day.....
Adam
😈😈😈
Sakira
such an socratic person?
Sakira
What Was Your Intention In Stating "Night Time Here" ?
Adam
please don't fight over silly stuffs!
Romancho
tangina mo
Sakira
No I Don't Believe A God Exist, But I Will Fight For Your Right To Worship Any God You Wish.....
Adam
no fighting
Sakira
But This Venue Is For Science Discourse.....
Adam
i know!
Sakira
No Fighting, Just Discussion.....
Adam
yes Naiyu, we have to use SI unit in the equation for the Kepler's every laws
Madhav
Thanks.
Naiyu
wow
Kenneth
Tell me about nebula
Asim
How it is created
Asim
Its a dust cloud of hydrogen
Asim
a nebula is usually formed when a star ends its life cycle
Chris
Ok
Asim
And its working?
Asim
When the time comes, most stars run out of available hydrogen they have for nuclear fusion
Chris
When that happens there is no more equilibrium between pressure and gravity
Chris
So there is no more pressure to balance the gravitational force, therefore a star collapses into its own core, and then the amount of matter inside the core is so large that the star explodes into a nebula
Chris
its a beautiful view, but very dangerous, the amount of radation is really big
Chris
Look it up on google, there are explanations better than mine
Chris
Ok thanks
Asim
what is your zodiac ?
Jenny
Gravity is the force that is formed due to the big mass of an object. The bigger is the mass, the bigger is the gravity. That is why the Earth attracts humans or small things. If We were bigger than the planet Earth we would have attracted it.
Lemisa
Tell me about white dwarf and red dwarf in simple words
Asim

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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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