Spaghettification

With a recent picture of a blackhole becoming the newest internet sensation I thought it might be neat to talk about my favorite word, spaghettification.

In class we’ve talked about tidal forces, that is the force differential between the close part and the far part to a gravitational source. On the small scale, such as Earth and its moon, it causes tides and the Moon tidally locked orbit. For those moons who have found themselves inside the Roche limit, these tidal forces can start to rip the moon apart and cause them to sucked into the planet. When the mass exerting the gravitational force becomes so large though the tidal forces start to get exaggerated.

space man getting spaghettified

This is where spaghettification comes in. If we look at the equation for gravitational force, F=(GMm/r^2) it shows that the radius term grows much faster than the mass terms meaning that as things get closer the force of gravity ramps up pretty fast. If we were to say that a value was twice as big as another, for numbers like 1 or 2 the difference would be small between the numbers, but for larger numbers the difference between some integer factor of these numbers is much larger. So if we consider the incomprehensible size of a black hole the difference between a front of an object and the back of an object will have extreme tidal forces. These extreme tidal forces act similar to the Roche limit as far as ripping apart the object but much more interestingly. Since the tidal forces are so extreme, on an atom by atom bases one atom will be accelerating much faster than its neighbor. This causes the atoms to travel towards the black hole in a single file line one after another much akin to spaghetti noodles; therefore, this process is known as spaghettification.

Life Off Earth

Recently, I have read an article on Scott and Mark Kelly during the Twins Study by NASA. As a serious skeptic involving the potential for the human species to persist in space, I was surprised by the findings in study.

Scott and Mark Kelly

In the study, Scott was sent into low Earth orbit while his twin brother Mark stayed on Earth. The goal was to test the resiliency of the human body and see if Scott demonstrated any threats to human longevity in space. Outside of a enduring sickness as Scott’s body readjusted to life outside of free-fall, he was healthy in all of the other aspects measured. Discrepancies were found, but these were somewhat anticipated as the body struggles against the new harsh environment that Scott had been flung into. The most surprising find, as mentioned in the article, was that while in space Scott’s telomere’s were elongated but quickly shrank back down after landing. Telomere shortening is the chief indicator of aging, so the fact that they grew is odd especially considering lifestyles such as high stress and low exercise can increase the rate at which they shorten. Some suggestion indicates this could have been due to a higher exercise regime and a better choice of nutrition.

Moving forward past low Earth orbit, there are other factors to consider. Once astronauts leave the tail of the Earth’s magnetosphere, solar winds could affect the human body in ways that the Twin Study could not predict. Additionally, this study did not address how the human body would react to illnesses in space. Also, even if an individual is capable of living an long healthy life outside Earth, the prospect of procreation seems like a huge endeavor; however, a 2001 study on rats does suggest that birth is possible in microgravity.

Overall, I am excited to see so much progress towards pushing the species to new reaches of the universe, but certainly it will be a rough time for the first pioneers who set out with full knowledge that they will live out their lives without the comforts of Earth that humans have evolved to used to.

Terraforming

Considering all the horrible ways that either humans or otherwise could end life on Earth, the idea of inhabiting another world seems pretty nifty. The only issue with that is we need oxygen and for our soft squishy skin to not get fried by intense sunlight. So, the prospects of getting off our planet for any indefinite amount of time outside the confines of some spacecraft seems grim. However, humans have proved that they can have some impact on the environment, so is it possible that we could sculpt, or “terraform”, a planet into one that is suitable for humans to live on?

In short, yes, but it is a rather complicated process. The first issue is that if whichever planet we choose to adapt does not have a strong core that spins fast then the magnetosphere would be too weak, or nonexistent, to sustain any atmosphere conducive for housing life. According to a Planetary Science Vision 2050 Workshop in 2017 we possess the current technology to artificially build a magnetosphere around a planet, but it requires giant rings that circumnavigate the world. Other ideas include building magnetic shields at some point between the planet and its sun to provide just enough blocking to mimic an Earth-like magnetosphere. Once the magnetosphere is established on most worlds volcanism will contribute to a build up of a greenhouse effect and global warming will start. If that world has water, which it probably does if it’s in the inhabitable region, the water will start to melt and finally provide a habitat suitable for microorganisms.

Wikipedia article on Mars terraforming

Rejoice!

After only a few extremely expensive scientific endeavors that did not fail at all the world could finally support some plants and small animals after a few hundred years. For reference, the estimate to make Mars inhabitable for humans is about 1,000 years.

Where is the Center of the Universe?

If you asked the ancient philosophers, they would have told you that Earth was the center of the universe. Perfectly stationary, the heavenly spheres revolved around Earth causing the celestial phenomenons we Earth dwellers witness each day and night. Modern science has debunked, rather profusely, the idea of geocentrism. Now, we can easily leave our atmosphere and witness the revolutions of the Earth around the Sun providing definitive proof that our planet is not at all special and the other bodies move throughout the cosmos without any care that we exist.

Cool. We are not the center of the universe. That makes sense and it is observable. But wait! Where is the center of the universe?

From a logical standpoint, one would look to the origin point and say, “Ah, yes. The center of the universe must be where the Big Bang took place.” This makes perfect sense if you assume that the geometry of the universe is a sphere; however, recently studies examining doppler shifts have suggested that the geometry of the universe, instead of being a solid, exists on a solid. This would make the “solid” that the universe rests on at least four dimensions since our world obviously exists in three dimensions.

The support for this comes from a large scale observation of doppler effects outside the Milky Way. Here’s a brief video that simply explains how that was observed.

So, now that the geometry has (somewhat) been determined we get to ask ourselves, again, “Where is the center of that shape?” Well, this turns out to be a difficult question. First, let’s ask the question, “Where is the center on the surface of a sphere?” If you think long enough, you might decide either that there is no center or that every point is the center. Start by picking any arbitrary point somewhere on the surface of the sphere. If you draw concentric areas around that point until the end of the surface you will discover that your arbitrary point provides perfect symmetry in every direction. This will hold for every possible point you could pick.

analysis via doppler

This concept translates to every regular surface of every solid, so we could apply this concept to our universe! This means that from an arbitrary standpoint we could choose any point in the universe to be the center, and in fact, this has been done for Tulsa, Oklahoma.

Turns out those ancient philosophers might have not been totally wrong.

 

Antipodal Tides

It makes sense that the tide comes in as the Moon approaches that side of the Earth. The gravitational pull attracts the water away from the Earth. It would seem them that logically a low tide would happen at a location farthest from the Moon. But that is not the case.

image link

In the Moon only scenario, the tides follow a 12 hour cycle and not a 24 hour cycle. The tide facing the Moon is called the sublunar tide, and the tide opposite the Moon is called the antipodal tide. But why does the antipodal exist?

An immediate explanation would be: “Oh, the Sun must be on the other side of the Moon pulling the waves in that direction!” But, in that consideration one fails to realize that the Moon is not always across from the Sun. A careful analysis of the location of the Moon during its different phases would make that clear.

So then how do we explain the antipodal tides? Turns out it’s kinda complicated and somewhat of a contentious topic. As seen in this stackexchange debate. What I find to be the simplest to understand is that as the Earth and the Moon pull on each other, there is an instantaneous force on each of them, and according to Newton’s Second Law, F=ma, there must an acceleration meaning that at any particular instant we can describe the Earth as moving towards the Moon. We know, obviously, that the Earth and Moon have constant mass, so according to Newton’s Law of Gravitation, F=(GMm)/r^2, the only variable is the distance between the the two masses. At the surface facing the Moon, the water is closer than the center of the Earth, so its acceleration will be greater meaning that any particular instant the surface facing the Moon is moving away from the Earth relatively. Likewise, the surface opposite the Moon has a force that is less than the center of the Earth, so its acceleration will be lower meaning that we can describe the Earth moving away from it or that it is moving away from the Earth relative to the Earth. This model of course becomes more complicated when the Sun gets involved, but for describing simply the phenomenon of antipodal tides I find it both useful and fascinating.

 

Historical Astronomers in Context

2. Galileo (15 February 1564 – 8 January 1642) was a hero of astronomy. Knowing that the Catholic Church did not uphold the views of Copernicus, he still pursued what he believed to be wholly factual science. After the Copernican revolution was rejected on the grounds that Aristotelianism was the product of the Divine, Galileo challenged those claims by providing observable evidence supporting heliocentrism. For this, he is named the father of observable astronomy and hailed as a champion of science. Interestingly, even with this conflict with The Church he still practiced Christianity devoutly.

3.a       1613- House Romanov was established in Russia. This was the ruling class that lead Russia through a tough history of comparatively lacking industry and development and out of the Times of Trouble; however, this primed them for a revolution after its collapse in 1917.

1600- The East India Trading Company was given a royal charter by Queen Elizabeth I. This trading super power dominated both militarily and economically over the Indian subcontinent especially over their French and Portuguese competition.

3.b       René Descartes– 31 March 1596 – 11 February 1650. This mathematician and philosopher was considered to be highly contentious and radical. Proclaiming that he would write and think as if no one had ever considered what he was studying. He is famous critically analyzing the way that mankind thought and departed chiefly from the authority of The Church on the premise that absolute certainty stems from mankind and not God assuming that mankind is totally autonomous.

4. It is fascinating to link the ideologies of Descartes and Galileo. Both believed in a particular flavor of truth that the Catholic Church was not willing to depart from. This methodology also manifested the need for practical evidence that could be repeatedly observed and verified. Logical deduction and then experimentation was the basis for every scientific pursuit that these two pioneers of thought investigated.

 

Galactic jet lag

In class, we discussed the implications and mechanics of light travel time. A major takeaway was the concept that because of the incredibly fast yet undeniably limited speed of light we are able to see VERY distant objects as they were VERY long ago.

If you are like me, you might try to see what this looks like at the extremes. So, I found myself asking a question. If we consider angles, would the diameter of an object not have an impact on the image if the center would get to us before the edges? Yes! the size of an object will have an effect on what we see, but the impact is much smaller than one might think. Let’s look at some scenarios:

relative size of milky way and distance to Adromeda not to scale

1. You are one light year away from 100,000 light year wide, face-on galaxy. Wow! This implies that the center of the galaxy is only one year behind us while the edges are 50,000 years in the past. That means that not only are these edge stars ancient, but they have also moved 50,000 years of traveling from where we see they are. The practical representation of this is our own galaxy, The Milky Way.
2. You are 70,000 light years away from a 10,000 light year wide, face-on galaxy. So, if you draw the triangles and use some basic trigonometry, you would find that the light-travel time-difference between Earth and the center and Earth and the edges is about 170 years which is about how long it took mankind to determine the universe has accelerate expansion after figuring out how to use stellar parallax which is rather profound. This describes our nearest galaxy, the Sagittarius Dwarf Galaxy.
3. Now consider a galaxy that is 2,500,000 light years away and 100,000 light years in diameter. In this scenario, the light-travel time-difference is approximately 500 light years between the edges and the center. Which is about the time it took mankind to discover water on Mars after Copernicus proved the Earth orbited the Sun.

First, I will address 2 and 3. In these scenarios I have described hundreds of years of difference in the position of the center and edges of galaxies. Could this describe why galaxies look spirally? In short, no. The spiraling effect this would have would be minimal and constant unlike the drastic and ever changing winding that takes place in spiral galaxies. This is understood when you consider the scale and speed of these galaxies. If our solar system and galaxy are typical then the average star orbits a galaxy at 0.0000004% of a rotation per year which means that for case 2 the position of the edge stars are only a mere 0.00007% percent of the full circle from where they should be, and for case 3, the number only rises to 0.0002%.

Okay, so lets do the same thing for case 1. The number only changes such that the furthest star in our own galaxy is 0.02% of it’s orbit behind where we expect it to be.

If anything this is a testament to how immense the universe is. That the time difference between two images can be so large and the macrostructure of galaxies appear unaffected is amazing.

If you want to see how dark matter affects the winding of galaxies, here is a video.

The Big Cheese

I’m a wonderer, so often times I wonder about odd things. Also, I have a nickname, The Big Cheese.

nickname, The Big Cheese.https://www.pinterest.com/pin/429741989423661504

Kinda related both of those things, today I’m going to be asking: “Where did the idea that the Moon was made of cheese come from?”

To start, I did a simple google search which lead me to Wikipedia. It turns out that people never believed the Moon was made of cheese. ~suprise~ But, it did potentially start as a folklore with that as the plot. Supposedly, a conniving Fox tricked a Wolf into descending into a well with the lure that the Moon’s reflection was cheese inside the well.

So then I thought, “When was cheese even invented? Like, could relatively modern astronomy be more recent than cheese?” Turns out that is a fat no. Another quick google search showed that cheese is has been around since circa 5500 BC well before the first telescope was even considered.

I mean it’s not totally unreasonable to believe that ancient people much like modern people are susceptible to horrific theories. Look at the Flat Earth Society. So, a sect of counter culture ancient people could have very realistically made up this theory when they were bored of farming.

 

The Journey Begins

Thanks for joining me!

Good company in a journey makes the way seem shorter. — Izaak Walton