What Would Happen If Two Galaxies Or Black Holes Became One?

Behold NGC 6357, “cathedral to massive stars.” Credit: NASA, ESA and Jesús Maíz Apellániz (IAA, Spain). (NASA/APOD)

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“NEW GALAXY DISCOVERED ORBITING THE MILKY WAY” You would think that scientists would have already discovered most of the galaxies around the Milky Way, but that does not seem to be the case. Astronomers have recently detected a dwarf galaxy orbiting the Milky Way called the Crater 2 dwarf. This galaxy was discovered through measuring its ‘half-light diameter’. Since galaxies don’t have actual definitive edges, astronomers measure galaxies by looking at the brightest part of the galaxy where half of the total amount of light from the it is emitted - half-light diameter. This galaxy has a half-light diameter of 7000 light years, which would look twice as big as the full moon if we could see it with the naked eye. Gabriel Torrealba and his colleagues at the University of Cambridge, the team that discovered this galaxy, was only able to find it by using a computer that looked for over-densities of stars in data (hinting at the possibilities of galaxies or something else) from images taken by a telescope in Chile. The galaxy has eluded the detection of the scientific community for so long only because its stars are spread out so thinly, giving it a ghost-like appearance. In addition, this dwarf galaxy is near four other new-found objects: the Crater globular star cluster as well as three dwarf galaxies in Leo - a group of objects that is now falling towards the Milky Way. Interestingly, this galaxy is quite new due to it retaining a round shape suggesting that it had never encountered a giant galaxy, otherwise gravity would have bent the dwarf out of shape.

Read more about this fascinating story on: https://www.newscientist.com/article/2084438-never-before-seen-galaxy-spotted-orbiting-the-milky-way/

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Oculus Superum, Red Nebula

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Hello there

As you can already tell, I haven't been really active (at all) on this account. The reason for this, to be honest, was the fact that Tumblr became stale to me, and besides that, I was very busy with my study for the university entrance exam for a year.

All of this caused this account to be abandoned for 2-3 years, which really not what I wanted at all because I created this account to help people with study and have reliable sources of information.

But I'm back (yay), and I’m trying to get back and resurrect this account again. There will be a few changes (since I changed a lot in the last few years).

1. My love for science is still there and even stronger now because... *drum rolls*... I’m studying science at university now! More specifically, biotechnology major, planning on an immunology minor. So yes, besides primary astronomy contents, I'm planning on posting more biology stuff! 

-> The name of this blog changed: study-astronomy-ref to study-astronomy-biology-ref

2. If you don’t know, this account is member-based. Even though I will be more active in the next few months, I can't be 100% be sure about keeping the account active for too long because of personal jobs and study. I had recruit more members for this account a while ago, but it didn't end well.

-> So if anyone wants to contribute to this blog as a pure studyblr, message, please. There, of course, will be standards and I will select the best people to run this blog smoothly, educationally and actively. For the best to everyone!

3. To me, this account is for people (very communism). So besides the science news, findings and study references, slide in the DM if you want something more interesting on this blog (science art? some Q&A? other cool science stuff?). I would be very happy if this blog could reach more people with similar interest and it could be a fun, wholesome and interesting place for anyone that has a passion for science and study! Wooray!

Maybe that's all I have to say. Stay tuned for more contents!

Head up to the sky, aliens. Keep on curious.

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This Year in Space (infographic)

From Pluto to the most Earth-like planet ever discovered…this years was a fantastic year in space. Here are the most notable astronomical events from 2015.

May you all journey well into 2016.

See all our infographics at: http://futurism.com/infographics/

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FAMOUS AUTHORS

Classic Bookshelf: This site has put classic novels online, from Charles Dickens to Charlotte Bronte.

The Online Books Page: The University of Pennsylvania hosts this book search and database.

Project Gutenberg: This famous site has over 27,000 free books online.

Page by Page Books: Find books by Sir Arthur Conan Doyle and H.G. Wells, as well as speeches from George W. Bush on this site.

Classic Book Library: Genres here include historical fiction, history, science fiction, mystery, romance and children’s literature, but they’re all classics.

Classic Reader: Here you can read Shakespeare, young adult fiction and more.

Read Print: From George Orwell to Alexandre Dumas to George Eliot to Charles Darwin, this online library is stocked with the best classics.

Planet eBook: Download free classic literature titles here, from Dostoevsky to D.H. Lawrence to Joseph Conrad.

The Spectator Project: Montclair State University’s project features full-text, online versions of The Spectator and The Tatler.

Bibliomania: This site has more than 2,000 classic texts, plus study guides and reference books.

Online Library of Literature: Find full and unabridged texts of classic literature, including the Bronte sisters, Mark Twain and more.

Bartleby: Bartleby has much more than just the classics, but its collection of anthologies and other important novels made it famous.

Fiction.us: Fiction.us has a huge selection of novels, including works by Lewis Carroll, Willa Cather, Sherwood Anderson, Flaubert, George Eliot, F. Scott Fitzgerald and others.

Free Classic Literature: Find British authors like Shakespeare and Sir Arthur Conan Doyle, plus other authors like Jules Verne, Mark Twain, and more.

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Textbook Revolution: Find biology, business, engineering, mathematics and world history textbooks here.

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KnowThis Free Online Textbooks: Get directed to stats textbooks and more.

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MIT Open Courseware Supplemental Resources: Find free videos, textbooks and more on the subjects of mechanical engineering, mathematics, chemistry and more.

Flat World Knowledge: This innovative site has created an open college textbooks platform that will launch in January 2009.

Free Business Textbooks: Find free books to go along with accounting, economics and other business classes.

Light and Matter: Here you can access open source physics textbooks.

eMedicine: This project from WebMD is continuously updated and has articles and references on surgery, pediatrics and more.

MATH AND SCIENCE

FullBooks.com: This site has “thousands of full-text free books,” including a large amount of scientific essays and books.

Free online textbooks, lecture notes, tutorials and videos on mathematics: NYU links to several free resources for math students.

Online Mathematics Texts: Here you can find online textbooks likeElementary Linear Algebra and Complex Variables.

Science and Engineering Books for free download: These books range in topics from nanotechnology to compressible flow.

FreeScience.info: Find over 1800 math, engineering and science books here.

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CHILDREN’S BOOKS

byGosh: Find free illustrated children’s books and stories here.

Munseys: Munseys has nearly 2,000 children’s titles, plus books about religion, biographies and more.

International Children’s Digital Library: Find award-winning books and search by categories like age group, make believe books, true books or picture books.

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PHILOSOPHY AND RELIGION

Bored.com: Bored.com has music ebooks, cooking ebooks, and over 150 philosophy titles and over 1,000 religion titles.

Ideology.us: Here you’ll find works by Rene Descartes, Sigmund Freud, Karl Marx, David Hume and others.

Free Books on Yoga, Religion and Philosophy: Recent uploads to this site include Practical Lessons in Yoga and Philosophy of Dreams.

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Religion eBooks: Read books about the Bible, Christian books, and more.

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ReadBookOnline.net: Here you can read plays by Chekhov, Thomas Hardy, Ben Jonson, Shakespeare, Edgar Allan Poe and others.

Plays: Read Pygmalion, Uncle Vanya or The Playboy of the Western World here.

The Complete Works of William Shakespeare: MIT has made available all of Shakespeare’s comedies, tragedies, and histories.

Plays Online: This site catalogs “all the plays [they] know about that are available in full text versions online for free.”

ProPlay: This site has children’s plays, comedies, dramas and musicals.

MODERN FICTION, FANTASY AND ROMANCE

Public Bookshelf: Find romance novels, mysteries and more.

The Internet Book Database of Fiction: This forum features fantasy and graphic novels, anime, J.K. Rowling and more.

Free Online Novels: Here you can find Christian novels, fantasy and graphic novels, adventure books, horror books and more.

Foxglove: This British site has free novels, satire and short stories.

Baen Free Library: Find books by Scott Gier, Keith Laumer and others.

The Road to Romance: This website has books by Patricia Cornwell and other romance novelists.

Get Free Ebooks: This site’s largest collection includes fiction books.

John T. Cullen: Read short stories from John T. Cullen here.

SF and Fantasy Books Online: Books here include Arabian Nights,Aesop’s Fables and more.

Free Novels Online and Free Online Cyber-Books: This list contains mostly fantasy books.

FOREIGN LANGUAGE

Project Laurens Jz Coster: Find Dutch literature here.

ATHENA Textes Francais: Search by author’s name, French books, or books written by other authors but translated into French.

Liber Liber: Download Italian books here. Browse by author, title, or subject.

Biblioteca romaneasca: Find Romanian books on this site.

Bibliolteca Virtual Miguel de Cervantes: Look up authors to find a catalog of their available works on this Spanish site.

KEIMENA: This page is entirely in Greek, but if you’re looking for modern Greek literature, this is the place to access books online.

Proyecto Cervantes: Texas A&M’s Proyecto Cervantes has cataloged Cervantes’ work online.

Corpus Scriptorum Latinorum: Access many Latin texts here.

Project Runeberg: Find Scandinavian literature online here.

Italian Women Writers: This site provides information about Italian women authors and features full-text titles too.

Biblioteca Valenciana: Register to use this database of Catalan and Valencian books.

Ketab Farsi: Access literature and publications in Farsi from this site.

Afghanistan Digital Library: Powered by NYU, the Afghanistan Digital Library has works published between 1870 and 1930.

CELT: CELT stands for “the Corpus of Electronic Texts” features important historical literature and documents.

Projekt Gutenberg-DE: This easy-to-use database of German language texts lets you search by genres and author.

HISTORY AND CULTURE

LibriVox: LibriVox has a good selection of historical fiction.

The Perseus Project: Tufts’ Perseus Digital Library features titles from Ancient Rome and Greece, published in English and original languages.

Access Genealogy: Find literature about Native American history, the Scotch-Irish immigration in the 19th and 20th centuries, and more.

Free History Books: This collection features U.S. history books, including works by Paul Jennings, Sarah Morgan Dawson, Josiah Quincy and others.

Most Popular History Books: Free titles include Seven Days and Seven Nights by Alexander Szegedy and Autobiography of a Female Slave by Martha G. Browne.

RARE BOOKS

Questia: Questia has 5,000 books available for free, including rare books and classics.

ARTS AND ENTERTAINMENT

Books-On-Line: This large collection includes movie scripts, newer works, cookbooks and more.

Chest of Books: This site has a wide range of free books, including gardening and cooking books, home improvement books, craft and hobby books, art books and more.

Free e-Books: Find titles related to beauty and fashion, games, health, drama and more.

2020ok: Categories here include art, graphic design, performing arts, ethnic and national, careers, business and a lot more.

Free Art Books: Find artist books and art books in PDF format here.

Free Web design books: OnlineComputerBooks.com directs you to free web design books.

Free Music Books: Find sheet music, lyrics and books about music here.

Free Fashion Books: Costume and fashion books are linked to the Google Books page.

MYSTERY

MysteryNet: Read free short mystery stories on this site.

TopMystery.com: Read books by Edgar Allan Poe, Sir Arthur Conan Doyle, GK Chesterton and other mystery writers here.

Mystery Books: Read books by Sue Grafton and others.

POETRY

The Literature Network: This site features forums, a copy of The King James Bible, and over 3,000 short stories and poems.

Poetry: This list includes “The Raven,” “O Captain! My Captain!” and “The Ballad of Bonnie and Clyde.”

Poem Hunter: Find free poems, lyrics and quotations on this site.

Famous Poetry Online: Read limericks, love poetry, and poems by Robert Browning, Emily Dickinson, John Donne, Lord Byron and others.

Google Poetry: Google Books has a large selection of poetry, fromThe Canterbury Tales to Beowulf to Walt Whitman.

QuotesandPoem.com: Read poems by Maya Angelou, William Blake, Sylvia Plath and more.

CompleteClassics.com: Rudyard Kipling, Allen Ginsberg and Alfred Lord Tennyson are all featured here.

PinkPoem.com: On this site, you can download free poetry ebooks.

MISC

Banned Books: Here you can follow links of banned books to their full text online.

World eBook Library: This monstrous collection includes classics, encyclopedias, children’s books and a lot more.

DailyLit: DailyLit has everything from Moby Dick to the recent phenomenon, Skinny Bitch.

A Celebration of Women Writers: The University of Pennsylvania’s page for women writers includes Newbery winners.

Free Online Novels: These novels are fully online and range from romance to religious fiction to historical fiction.

ManyBooks.net: Download mysteries and other books for your iPhone or eBook reader here.

Authorama: Books here are pulled from Google Books and more. You’ll find history books, novels and more.

Prize-winning books online: Use this directory to connect to full-text copies of Newbery winners, Nobel Prize winners and Pulitzer winners.

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Use studying techniques to your advantage:

Got these notebooks for 5 cents so obviously going to buy more than one :D # strongnotebookgameisstrong

There’s a method to my madness I swear!! OK so on avg I seem to use up two of those 80 pg notebooks so I got two for each class. And consequently I needed the 4pack 32pg exercise books. 

The 80 page notebook is used for in class notes. As soon as anything important is said it is scribbled down into the notebook.  The 4 pack 32 pg exercise book is divided to two groups: Feymann technique and Cornell method.

Feymann Technique

Right after class I grab my textbook, my notebooks and two of  my exercise books. I teach myself the lesson primarily with my notes and if I don’t understand something I turn to my textbook. If I am still lost I leave space and note that there is something I need to clarify with my professor. Even while I am doing this, I force myself to decrease the writing and increase the connections between every topic since the 32 pg is quite smaller than the 80 pg. 

Thankfully when I am done with this, my 32pg becomes the go to whenever it seems like I am in need of revising a topic since it contains relevant notes from both my textbook and my notebook in my own words. 

Cornell Method.

When exam time approaches I convert my notes into the cornell notes so that I can easily test myself with the main ideas and key questions.

There is no better way to revise than to try to make connections. That is all you are going to get tested on since it’s not that hard to spit back words on a page. Instead of being asked about photosynthesis for example, you might be told about some chemical that is sprayed on a plant that will block one process and asked about how that affects the growth of the plant overall. See what I mean? 

I usually get a whiteboard and write all of the connections out and in front of me. When THAT  is done I write it down in flashcard mode and quiz myself for the next week using the Leitner system, along with the topics that are basically just memorization.

LEITNER SYSTEM

Label 5 boxes 1-4, where 1 is for cards you don’t know and 4 is for cards you are basically a pro in. You frequently test yourself in box 1 (maybe every 30 mins, you choose) and increase the time in which you test yourself until you reach 4, where you would test yourself just once a day. 

In the beginning all of your cards go in box 1,and as you get a card right it goes up a level and if you get it wrong it goes down a level. That way you are spending more time with ideas and topics you don’t have a strong hold on, rather than spending equal time with all the topics. 

At this point I have rewritten my notes twice in my own words and then converted them into flashcard mode :) I recommend this method when it comes to the sciences or humanities. For the maths I have already done a post about it here. 

Hope this helps for those still looking for study techniques! 

-F 

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Goodness look at the interplay between the light of the setting sun and the wave!!

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Can you explain in a simple (???) way gravitational waves? please? do you know any books about it?

Sure!

According to Einstein’s General Theory of Relativity, what we think of as "empty space” isn’t nothing. Instead, space is more like a fabric that can be stretched, squashed, bent and shaped, and all matter and energy cause space to bend around them. The more mass or energy something has, the greater the bending of space around it it causes, a bit like heavier and lighter balls on a rubber sheet:

(Source - Note that this picture is a 2D analogy, and space is actually 3D! The bending of space isn’t something we can easily visualise, so we have to use analogies like the “balls on a rubber sheet” analogy - as long as we recognise their shortcomings!)

Let’s imagine the Sun is a bowling ball dropped onto a rubber sheet, creating a huge dent in space. And now let’s roll a marble - Earth - onto that sheet too. IF the marble is rolling too slowly, it will fall into the dent and roll around a few times, spiralling in and eventually colliding with the ball. If the marble is rolling too quickly, its path will be bent, but it will escape. If it’s rolling at a certain speed, however, the marble will roll around the bowling ball and go into orbit around it. (Here’s another shortcoming of the rubber sheet analogy - real rubber sheets have friction, so the marble would eventually slow down and roll in towards the bowling ball. Space, however, has no friction, so the Earth can stay in orbit around the Sun for a long time.) In other words, this bending of space is what we refer to as gravity!

In Newton’s view of gravity, Earth would naturally follow a straight line through space, but its path would be bent towards the Sun by a mysterious pulling force. That force holds the planets in orbit around the Sun and pulls apples to Earth, but Newton couldn’t explain why - a mysterious influence that spread out through space, called the gravitational field, somehow caused bodies to attract one another. Einstein explained that massive objects curve the space around them. Earth would also naturally follow a straight line through space, but the space itself is curved, forcing Earth to follow a curved path - it’s a bit like trying to walk in a straight line along a hill. Try as you might, your path will have to bend to follow the contours of the landscape. According to Einstein, gravity isn’t really a “force” as such but an effect of this bending of space. Matter and energy tell space how to bend; space tells matter and energy how to move. That’s all gravity is. The gravitational field isn’t some mysterious entity in space - the gravitational field is the space itself! Here’s a nice little video to help you visualise all this:

(I’m oversimplifying a little, btw, saying that gravity is the bending of “space.” In Einstein’s theory, the three dimensions of space are unified with time into one four-dimensional fabric, the space-time continuum. So gravity isn’t just the bending of space, but the warping of time too - you can’t change one without changing the other! Gravity actually slows time down, so you would age slightly faster in space than you do at Earth’s surface. The difference is incredibly tiny, but measurable - time passes more quickly for the GPS satellites than it does for us here on Earth, and what the clock of a GPS satellite would measure as “one day” is about 38 microseconds shorter than what we measure as “one day.” That doesn’t sound like a big difference, but engineers have to take it into account when designing GPS systems - if they didn’t account for this, your GPS location would drift by as much as 10 kilometres per day! So this isn’t just some abstract theory - this is a real effect that’s already important for technology you probably use every day.)

General Relativity has now been through many, many tests and has passed every one with flying colours, and all of its predictions had been verified by the beginning of 2016 except one - gravitational waves.

What would happen if we could somehow destroy the Sun? Newton believed that there was a mysterious gravitational connection between the Sun and Earth, holding Earth in its orbit, that would instantly be broken if the Sun was destroyed. Earth would instantly fly out of its orbit in a straight line. Einstein, however, didn’t like this - his Special Theory of Relativity (which he put out 10 years before the General Theory) says that no information could ever travel faster than light. It takes about 8 minutes for the Sun’s light to reach us, so how could Earth fly out of its orbit instantly? That would let us know the Sun had been destroyed 8 minutes before the light from the Sun’s destruction reached us. Einstein wasn’t comfortable with this.

Thankfully, General Relativity resolves the paradox - if you got rid of the Sun, Earth would still stay in its orbit for a while, because the space-time around the Sun would still be curved. Meanwhile, at the place where the Sun was, space-time would spring back to its original flat state, and that would ripple through the surrounding space-time as everything adjusted back to where it was. That ripple - a gravitational wave - would spread out through space at the speed of light, so the space around Earth would stay curved and Earth would remain in its orbit until the same time the light from the Sun’s destruction passed us - at which point the gravitational wave would ripple through the space around Earth and restore it back to its original flat state, and Earth would finally leave its orbit.

Of course, in reality, stars don’t just disappear. But the gravitational environment does change. Stars move around, and the fabric of space-time also moves with them. Stars explode. Black holes and neutron stars form, putting huge dents in space-time, and sometimes they collide. All these events are a bit like changing the environment in a still pond - stars and planets gently orbiting are like ducks gently gliding through the pond, creating gentle ripples as they disturb its surface - and black hole collisions are more like throwing a rock into the pond and sending out massive waves. Almost everything in our universe produces gravitational waves, but most of the time, they’re too tiny to detect. (That’s why I said in real space the Earth can orbit the Sun for “a long time,” and not “forever.” Earth is constantly sending out very faint gravitational waves as it rolls around the Sun and moves through the fabric of space-time. Those waves are too small to detect, but they very, very slowly sap Earth’s energy and cause it to very, very slowly spiral in to the Sun. In reality, that would take unimaginable trillions upon trillions of years, and Earth will probably be destroyed by the dying Sun long before that! Even if Earth manages to survive that, it’s more likely to be pulled out of orbit by an incredibly rare passing star or knocked out by unpredictable gravitational tugs from the other planets or something before it spirals into the Sun. Orbits are stable for a very, very, very, very long time.) More intense sources of gravity than our puny Earth and Sun, however - things like neutron stars and black holes - can generate detectable gravitational waves.

Our first indirect evidence of gravitational waves came in 1984, when the American astronomers Russel A. Hulse and Joseph A. Taylor discovered a binary neutron star system - two intense sources of gravity orbiting each other very rapidly. As they orbited each other, they sent out huge gravitational ripples - a bit like stirring up that duck pond with two oars whirling round and round - and lost energy by a detectable amount. Hulse and Taylor found that their orbital period slowed down by about 75 milliseconds per year - short, but detectable! That slowing exactly matched the predictions of gravitational wave theory and got its discoverers the Nobel Prize for Physics in 1993.

(Source)

But gravitational waves weren’t directly observed until 2015 (and confirmed until this year) by a detector named LIGO (the Laser Interferometer Gravitational wave Observatory). All LIGO is is basically two beams of laser light travelling between two pairs of mirrors oriented at right angles to each other, like this, so you can measure how space-time is stretched in one direction and squashed in the other by a passing gravitational wave by recording how long it takes the light to travel from one mirror to the other*:

(Source for both images: http://phys.org/news/2016-02-ligo.html)

LIGO’s two “arms” (the two beams of light) are each 4 kilometres long, and a gravitational wave passing through the detector stretches or squashes each of the “arms” by a ridiculously small amount - the ones LIGO actually found stretched and about 1/10,000th the width of a proton. As you can imagine, the LIGO physicists had to account for many, many different effects that shook the detector too. But gravitational waves distort the two beams in a predictable way that would make that distortion stand out from ordinary passing trucks or distant earthquakes, and by February 11th, 2016, the LIGO physicists were confident enough that they really had detected a faint ripple in space-time passing through their detector. The signal was consistent with a gravitational wave from two black holes in orbit around each other, spiralling in to one another.

(Source)

This is exciting for two reasons:1) It confirms the last outstanding prediction of General Relativity, and2) It opens up a whole new field of astronomy! Every so often astronomy is revolutionised by the discovery of new things we can look at from space. Originally all we could detect was the visible light that we could see with our eyes and telescopes. But soon we learned to build radio telescopes, and that opened up a whole new world to us - we could see phenomena that were invisible in ordinary light. With space telescopes we could see the sky in gamma rays, x-rays, ultraviolet and infra-red light as well. Now we could see the explosions of distant stars halfway across the observable Universe, look at clouds of gas and dust too cool to shine in visible light, and peer through other dark clouds to see stars forming inside. We also found particles we could see coming from space, too - neutrinos from the Sun and from supernovae, and cosmic rays. These opened up other windows on the Universe. And now we have gravitational waves - yet another new way of “seeing.” Gravitational wave astronomy will let us study some of the most puzzling events in the Universe, like colliding neutron stars, or black holes falling into other black holes - events we’ve never been able to see before. 

So I hope that helps, Anon! 

As for books, the problem is gravitational waves were detected so recently I don’t know of any books that have come out since then on the subject, so everything will be out of date. However, the basic physics has stayed the same since Einstein first predicted them, so any good popular book on general relativity (Spacewarps by John Gribbin, The Fabric of the Cosmos by Brian Greene and Travelling At the Speed of Thought: Einstein and the Quest for Gravitational Waves by Daniel Kennefick are good examples) should give you some good insight - just replace phrases like “if we detect gravitational waves” with “when we detected gravitational waves!”

(*Yes, yes, I know LIGO isn’t actually measuring the time taken for light to travel down each “arm,” but the interference of the laser beams. Still, that interference allows us to infer the travel time for the light, so I’m simplifying.)

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Strap in for a Tour of the Milky Way

The night sky isn’t flat. If you traveled deep into this part of the sky at the speed of the radio waves leaving this tower, here are some places you could reach.

Jupiter: Travel time – 35 minutes, 49 seconds.

The closest object in this view is the planet Jupiter, brilliant now in the evening sky…and gorgeous when seen up close by our Juno spacecraft. Distance on the night this picture was taken: 400 million miles (644 million kilometers). 

Saturn: Travel time – one hour and 15 minutes.

The next closest is Saturn, another bright “star” in this summer’s sky. On the right, one of the Cassini spacecraft’s last looks. Distance: 843 million miles (1.3 billion kilometers).

Pluto: Light-speed travel time from the radio tower – four hours, 33 minutes.

It’s not visible to the unaided eye, but Pluto is currently found roughly in this direction. Our New Horizons space mission was the first to show us what it looks like. Distance: more than 3 billion miles.

F-type star, HD 1698330: Light-speed travel time from the radio tower – 123 years.

Within this patch of sky, there’s an F-type star called HD 169830. At this speed, it would take you 123 years to get there. We now know it has at least two planets (one of which is imagined here) — just two of more than 4,000 we’ve found…so far.

The Lagoon Nebula: Light-speed travel time from the radio tower – 4,000 years.

If you look closely, you’ll see a fuzzy patch of light and color here. If you look *really* closely, as our Hubble Space Telescope did, you’ll see the Lagoon Nebula, churning with stellar winds from newborn stars.

Black hole, Sagittarius A*: Light-speed travel time from the radio tower – 26,000 years.

In 26,000 years, after passing millions of stars, you could reach the center of our galaxy. Hidden there behind clouds of dust is a massive black hole. It’s hidden, that is, unless you use our Chandra X-ray Observatory which captured the x-ray flare seen here.

The next time you’re under a deep, dark sky, don’t forget to look up…and wonder what else might be out there.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

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