Space, In Perspective

We're star stuff, contemplating the stars.

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Welcome to Space In Perspective!

This blog is no longer active, but it’s full of wonders to explore.

Click here to browse through topics you may be interested in. Click here for a list of Frequently Asked Questions. Click here to learn about me.

You can also find me on Twitter and read my personal blog. I am available for freelance science writing and editing. View my portfolio here.

Please consider the context in which this blog was written. Forgive any factual errors, social faux pas, insensitive jokes, ignorant opinions, or careless wordings. Science, the world, and the internet were all very different when I was a teenager writing this in 2009. I have not revisited any of the posts to edit them for palatability; I ask for a generous benefit of the doubt here.

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we’re about to begin a journey through the cosmos

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“If you don’t like Mars, I don’t like you.”

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A photograph of the Saturn and its rings, taken by the Cassini spacecraft from inside the planet’s shadow.  Earth is visible in the upper right as a small dot between rings.  (High Res)

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Earth.

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Merry Christmas to all! Here is an original Christmas carol written and recorded by Canadian astronaut Chris Hadfield while on the International Space Station. Yes.

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PREACH.

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ISS in front of the moon.

[Photo credit: Thierry Legault]

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If global society decided to just let go of its inhibitions and ya know fed all the third world countries, started farming correctly, let go of our obsession with personal gain and realized we have to act as a species... could I see space travel in my life time? If we all snapped out of it... I think we would have incredible advances in space travel and general exploration of things we don't understand and it's exciting to me that me and my generation could witness such things.

Perhaps.

The biggest thing holding back space exploration is lack of funds. That's also a major player in a lot of world issues: money. Which, the concept of money is ridiculous and sort of stupid in the first place, but that's beside the point. The level of global thinking necessary to solve the problems you mentioned is very far beyond the way we're acting now. Once we create a global community and shed the chains of the problems we face now (manipulation, inhibition of liberty, moneygreed, poor diet, lack of eduction, etc.), will space exploration really be the top priority? Should it be?

Space exploration is not the end all be all of human progress. I think that if we "snapped out of it", so to speak, space exploration would be far less of a big deal than it seems to us now, though I'm sure we'll still do it to great success.

It's tough, though. The way that our intelligence and maturity as a species will ascend at that point is sort of beyond. Who knows what we'll be thinking? Who can predict something as chaotic as the global hivemind? I'm not convinced that there's a Rivendale-like world of perfection in our future with peace and prosperity ringing true for all of mankind. So it's tough to speculate on this. I think the most important thing right now is educating people and ending prejudice. From there, the framework of an intellectual, scientific, and emotional revolution will fall into place.

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I'm a Physics major, and I want to study "space stuff" when I get to grad school. What's a good field to focus on (e.g., General Relativity, Optics, Cosmology, etc)? And what's a good grad school for studying this? :)

In grad school, you typically will go either theoretical or experimental. Theoretical physicists do a lot of reading, math and philosophy. Experimental physicists do a lot of data processing, math, and computer programming.

From there you choose a specialty. That's the tough part. Talk to every professor in the physics and astronomy department(s) and ask them about their research. That is honestly the most important thing you could do. Another thing to try: think of the most interesting question in physics, the one question you are most interested in having answered. Answer it. Make that your field. A good field is one that you can dedicate yourself to! You should focus on what you want to focus on.

That said, there are certain areas where "new physics" is happening. Old physics is considered to be areas where technology is not caught up with our experimentation and theorization. That would be accelerator physics, unification (to some extent), and particle physics. New physics is major breakthroughs in understanding. The newest physics is happening in biophysics, medical physics, cosmology, nuclear physics, quantum technologies, and quantum mechanics. Other solid fields are condensed matter physics, plasma physics, chemical physics, geophysics, crystallography, and laser physics. 

I'm going to say some obvious things about grad schools: the schools you think are good for physics are the ones that are the best. Harvard, MIT, Cornell, Caltech, Princeton, Stanford, Columbia, etc. There are also good public schools: UCLA, UC-Berkeley, UC-Santa Barbara, UT-Austin, University of Illinois, University of Michigan. If you want to go into Medical Physics then Johns Hopkins University is obviously tops. Here is a ranking of physics grad schools. You can even sort them by specialty!

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What are your plans for the end of the world tomorrow?

With all of the impending doom and deathstruction and the unspeakably gruesome pain and suffering that will be upon us on the 21st, do you have plans for living out your last few remaining hours of existence?

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Earth’s time remaining

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If a person lived on the moon, would the decreased gravity affect their health or lifespan in any way?

Absolutely!

The major immediate effect would be muscle atrophy and bone density decrease. Astronauts on the ISS struggle with this. No matter how much they work out with weights up there, they still are not utilizing their muscles and bones in the same way, so their bodies eat away at the unused material. Someone on the moon would need simulated gravity and an intense workout regimen, but they would experience fewer negative results from this than those on the ISS—the moon has at least some gravity, whereas the ISS has none.

Someone living on the moon would be exposed to a significant amount of radiation from the sun-facing side of the moon. There is no atmosphere or ozone layer to absorb the rays of the sun. It's also very hot on the sunny side of the moon—the temperature averages 92ºC (197ºF), but that's less of an issue than the unhindered radiation. They'd need some hella sunscreen and some very legit sunglasses.

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Another word about time travel...

Spacetime is a single substance; to talk about space and time separately is nonsensical. When you want to travel in time, you must also consider travelling in space (see above). So when anyone mentions travelling backward or forward in space and time, one must consider the complicated nature of physical location in that. There is a lot to consider there. The earth is moving, the Sun is moving, the galaxy is moving, the universe is expanding. This is another reason that time travel as we imagine it is a lot further off than we would all like to hope.

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Have a cool question about ~space~ or ~time~ or ~physics~ or ~anything~? Ask away and it will be answered in the order of most interesting and/or the extent to which I can satisfactorily answer it!

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Is time travel possible?

Yes! But maybe not the way you're thinking.

We can (sort of) travel forward in time by going very fast. As you approach the speed of light, time passes significantly more slowly. Astronauts who spend six months on the ISS may feel like they have been up there for six months and one second, while on Earth, we have felt six months and two seconds. The effect grows as you increase your speed. If one goes 80% the speed of light, it might take six years to reach Alpha Centauri, while on Earth it will feel as if ten years have passed. At the speed of light, time does not pass. A photon may travel billions of light years, but it feels immediate for the photon.

The implications of this are that if you want to travel to the future, you would have to go very fast and then return to earth. That's impractical, however, and likely won't be achieved. We are not completely sure how all this works, but it's theorized by some that if we fully utilize the properties of wormholes (which we still have not discovered concrete evidence of), we may be able to travel forward and backward in time and space as we please.

Traveling forward in time is the non-issue here, philosophically, though the technology is many years off still. Traveling backward in time is the real problem for our brains. Take Barjavel's famous Grandfather Paradox:

If someone travels back in time and kills her grandfather when he is a child, then her grandfather never has her father, and therefore the traveller never could have been born to travel back in time to kill her grandfather.

This of course rings true with killing other family members paramount to your own birth, and also with "autoinfanticide", or, going back in time and killing yourself as a baby.

There are a few ways we get around this.

Novikov self-consistency principle, a.k.a., the Harry Potter model. Any action that you take after returning to the past was always the action that happened. For instance, take the scene in The Prisoner of Azkaban when they are all at Hagrid's place and a rock comes soaring through the window, causing them to see that the executioner is coming. Later on, Hermione and Harry go back in time and, seeing that they need to warn their past selves of the approaching executioner, Hermione throws a rock in the window. Therefore, every action she took in the past was always going to happen, and she fulfilled it by actually going back and doing it. This model is used heavily in Doctor Who.

Parallel universe theory #1: Nonexistence Theory, a.k.a., the It's A Wonderful Life model. You travel back in time, and upon returning to the future, you see the consequences of your actions. If you cause something that leads to your nonexistence (killing your grandfather is one such action), then return to the future, you will find yourself in a timeline where you never existed, though obviously you would still exist. It would be an alternate timeline where your life never happened. You existed in the past, and you exist now, but you did not exist in between.

Parallel universe theory #2: The Butterfly Effect. You go back in time and you accidentally step on a butterfly. The butterfly in the future was going to land on a boy's face and cause him immense joy. Since you killed that butterfly, the boy never experiences that joy, and grows up sad, then becomes an evil dictator. The Butterfly Effect theory states that by simply existing in the past, you are creating a new timeline. You may step on a microbe, or carry a virus to someone, or do some small action that has massive results. Often, massive things start with small actions. The Butterfly Effect is a realistic testament to the connectedness and importance of every single atom and every action of every being to the universal ecosystem.

The most likely answer is that when you travel back in time, you create a parallel universe. Many versions of multiverse theory state that there are a infinite number of universes, each with a different timeline. There is a universe for every "what-if" moment on earth, and every other planet in every galaxy. There's a universe where you're reading this on a train, and one where you're reading it in a park, and one where you're reading it and you have blue skin, and there are an infinite number of universes where everything on earth is exactly the same and things on other planets go differently. So if this multiverse theory is correct, and you travel back in time, is it possible that with every action you take, you are travelling between universes into other timelines?

Our understanding of time and space and multiverses is not quite there yet. We may never know the philosophical answer to time travel, even if we ever figure out the physical answer.