There's nothing worse than wanting to expand your knowledge, satisfy your curiosity, or just confirm some weird historical fact, and getting blocked by a paywall or the sad reality that what you need is tucked away inside a book that you have to go to an actual library to find. You know, outside, away from the comfort of your computer.

Fortunately, the custodians of content are finally figuring out that if you give people easy access to the things they want (for free if possible, please), everybody wins, and if not, well, someone will probably find a less 'legal' way to get it out there instead. Knowledge is everything, and we want all of it, now, and who can blame us?

You might not be ready to ditch your Netflix account so you can just sit there and pore over Einstein's Archives for hours (kudos to you if that's your thing, you're a better person than us), but just knowing where to go to get that particular resource for free right when you need it is everything.

So we've come up with a list of great, free online repositories that offer everything from historical documents by your favourite scientist to beautiful sci-fi posters to put on your wall. If you've got suggestions for other online resources, email us or post a comment on Facebook so we can spread the (free) science love!

1. Millions of science papers are available for free online via Sci-Hub

Nicknamed the 'Pirate Bay of Science', Sci-Hub is the brainchild of neuroscientist Alexandra Elbakyan, who's positioned herself as something of a Robin Hood figure in the endless 'push-and-pull' of paid journal access. Want to look up a quote in a scientific paper? That'll be $40 to read a single, digital paper, please.

Without getting into the whole issue of our tax dollars funding the research that journal publishers charge an exorbitant amount of money for us to access, scientific knowledge was never supposed to be locked behind a paywall. As Fiona MacDonald explained last month:

"[J]ournal publishers have also done a whole lot of good - they've encouraged better research thanks to peer review, and before the Internet, they were crucial to the dissemination of knowledge. But in recent years, more and more people are beginning to question whether they're still helping the progress of science. In fact, in some cases, the 'publish or perish' mentality is creating more problems than solutions, with a growing number of predatory publishers now charging researchers to have their work published - often without any proper peer review process or even editing."

So if you need access to a particular scientific paper, check Sci-Hub first. It might not be around forever, so enjoy this absolute treasure trove while it lasts.

2. Over 16,000 pages of Darwin's research on evolution

Released on the 155th anniversary of the publication of Charles Darwin's iconic work, On the Origin of the Species, 16,000 high-resolution images of his research on evolution were released online to the public. It took the American Museum of Natural History's (AMNH) Darwin Manuscripts Project seven years to get over half of them digitised, and more are being added all the time.

The AMNH says the documents released "[C]over the 25-year period in which Darwin became convinced of evolution; discovered natural selection; developed explanations of adaptation, speciation, and a branching tree of life; and wrote The Origin." Access them all here.

3. All of Richard Feynman’s physics lectures

Richard Feynman was something of a rockstar in the physics world, and his lectures at Caltech in the early 1960s were legendary. While footage of these lectures can be found on YouTube if you know where to look, for many years, the best resource for all things Feynman was a three-volume collection of books called The Feynman Lectures.

Fortunately for us, what become the most popular collection of physics books ever written has been made available online for free at the the Feynman Lectures Website. Every piece of content, equations and all, has been designed to be viewed on any kind of device. Happy learning!

4. Incredible high-res photos of the Apollo missions are available for download on Flickr

You might think you’ve seen photos of the Moon landing before, but you haven’t seen that epic achievement properly until you've seen these awe-inspiring pics. NASA recently published 9,200 high-resolution images from the Project Apollo Archive on Flickr, taken during every manned mission to the Moon, both on the way there and back.

Just try not to spend your whole time sighing wistfully as you peruse this incredible archive, as hard as that might be.

Project Apollo Archive

5. NOVA Science Now documentaries are free to watch online

Want to peer into Einstein's brain and learn how to seriously boost your memory capacity? Or do you want to see incredible mind-reading machines and virtual environments that might one day become a part of our everyday lives? NOVA's Science Now documentary channel is giving free access to a selection of its documentaries, which you can stream online here.

They've got 23 full episodes online right now, and they're being updated all the time, so stop binge-watching House of Cards for a sec and educate yourself on GANGSTER BIRDS.

6. Thousands of Einstein documents are available for free online

The New York Times once called them the "Dead Sea Scrolls of physics", and now you can access as many of them as you can get your digital hands on. Back in 2014, Princeton University launched the Digital Einstein Papers project - an open-access site that delivers the extensive written legacy of Albert Einstein to the public - some 80,000 documents, to be exact.

Spanning from the years of Einstein's youth through to old age, the project has made all kinds of letters, papers, postcards, notebooks, and diaries that Einstein left scattered in Princeton and in other archives, attics, and shoeboxes around the world when he died in 1955 available to the public, and we are so lucky to have such easy access to them now. Click here to access them.

7. NASA has released high-resolution files of its awesome 'space tourism' posters for download

We promised something pretty to put on your wall, and here they are: the entire collection of NASA's "Visions of the Future" space tourism posters, which includes scenes of tourists ballooning around the purple haze of Jupiter's aurorae (that are literally bigger than the entire Earth) and hoofing it through the extensive subterranean aquariums of its moon Europa (scientists suspect there are liquid oceans churning beneath its icy surface).

Not restricted to the planets within our Solar System - they also have an exoplanet collection - the posters might be fantastical, but the designers at NASA's Jet Propulsion Laboratory have based everything you see on real science. Check out the full collection for download here.

8. The entire run of IF Magazine

Finally, if your brain is done for the day and you just want to curl up with some awesome science fiction, check this out: the entire archive of IF Magazine, an American science fiction magazine launched in March 1952, now available for free online.

Andrew Liptak from Gizmag explains what's on offer:

"IF never quite reached the same pinnacle as that of other magazines such as Astounding Science Fiction, the Magazine of Fantasy and Science Fiction or Galaxy Science Fiction, but it published a number of excellent stories and serialisations, such as James Blish’s classic story "A Case of Conscience," and Harlan Ellison’s "I Have No Mouth and I Must Scream," and works from authors such as John Brunner, E.E. "Doc" Smith, Joe Haldeman, Poul Anderson, James Blish, Frederik Pohl (who also edited the magazine), James E. Gunn, and many, many others."

Even if you don't feel like reading any of it, just take some time to look at the awesome illustrations. Astronauts are carrying a very satisfied dinosaur somewhere, and we're so glad we were there to see it.