As humans have logged more and more time in space over the last half-century, researchers have been able to collect more data on the impact of prolonged spaceflight on the human body. This data is mostly anecdotal, with astronauts recounting their experiences for aeromedics (yes, that’s a real thing) upon their return to Earth. Other effects were predicted as results of basic understandings of physics and physiology well before humans entered orbit.

The most significant impact on the human body in space comes from the lack of gravity. Since our legs no longer have to support our weight while in space, there is significant muscle atrophy as well as decalcification of the legs, pelvis, and spine. Some researchers have estimated this effect to be up to 12 times that of osteoporosis. The excess calcium has also been known to cause kidney stones. Another known issue of experiencing microgravity is disorientation. The system that our brain relies upon to tell up from down is based upon fluid chambers located in our inner ears. Without gravity, the fluid floats in a neutral position. Many astronauts have reported suddenly feeling as if they were upside-down. Others say that they lose a perception of where their arms and legs are in relation to their body. Remarkably, these effects are known to dissipate after a few days. Apparently, the brain quickly shifts to relying only on sight orientation after the ear fluids are no longer reliable. One more effect of microgravity is the redistribution of body fluid. Gravity on Earth tends to concentrate blood and other fluids towards our lower extremities. Without that force, the fluids move towards the head, resulting in a swollen face and nausea.

Another phenomenon has to do with the lack of a normal day and night while traveling in space. While on Earth, our sleep cycles tend to coordinate with the sun, which is often referred to as our “body clocks”. In space, your position relative to the sun can be somewhat arbitrary, meaning your body clock cannot set itself. This has been known to decrease sleep totals in space as well as decreased energy and productivity while awake. Some researchers have experimented with artificial day/night lighting aboard spacecraft to increase sleep and productivity.

Luckily, neither of the preceding issues have serious long-term effects. The astronaut’s body will almost certainly recalibrate upon return to earth. The one permanent issue, however, is increased exposure to radiation. Without the protection provided by the Earth’s atmosphere, astronauts are exposed to radiation levels at least 10 times that of a human at the face of the Earth. Radiation has been known to damage the immune systems of astronauts as well as increase the likelihood of cancer and cataracts. These effects are not immediate, and unfortunately will show up many years later. Astronauts usually see these long-term effects as a small price to pay for the opportunity of a lifetime, but some have come to regret their time spent in space when these effects surface later in life.

While doing some readings for my most recent blog post, I came upon an article written in 2005 that anticipated results from a new NASA project with an anticipated launch date in 2010. Being that it is 2014, I assumed that there would be some results available from that project. However, with a little more reading, I discovered that project has been postponed until 2034 due to budget constraints. That got me thinking about the future of NASA and its role moving forward.

The first noticeable trend is that manned spaceflight is probably not reasonable at this point and may become obsolete moving forward. Since man landed on the moon, unmanned spacecraft have become exponentially more useful. As Charles Seife at Slate points out, the International Space Station has essentially been fruitless in terms of reaching its research goals. In contrast, unmanned spacecraft have been collecting Nobel Prize-winning data for years. Furthermore, 4% of US astronauts have perished on their missions, which is in many ways an inexcusable number. Until it becomes feasible to place men on Mars, there may not be manned space-travel for these reasons.

Image Source: NASA Budget

Maybe even more troubling, the projected NASA budget for 2015 shows a 24% decrease in the education sector. Arguably one of NASA’s most lasting impressions on the public has been inspiring the next generation of scientists and innovators. Space has always been able to capture the human imagination, and there is no exception when it comes to schoolchildren. As Neil deGrasse Tyson puts it: “If I say, ‘Design me a plane that’s more fuel-efficient, because the country needs that now,’ you’re not going to get any truly transformative, innovative solutions. Instead, if I say, ‘Who wants to build an air foil that’ll navigate the rarified atmosphere of Mars?’ or ‘We’re about to go to Mars. Who wants to study life forms that are yet to be understood that we may discover?’ I’m going to get the best engineers, I’m going to get the best biologists.” Space and its frontiers have been able to bring about the best in human innovation for generations, and if NASA loses the capability to inspire students across the country, irreparable damage may be done to the next crop of engineers and explorers.

Sources and Further Reading:

http://www.theatlantic.com/technology/archive/2012/03/neil-degrasse-tyson-how-space-exploration-can-make-america-great-again/253989/

http://www.slate.com/blogs/bad_astronomy/2014/03/05/nasa_budget_2015_more_cuts_more_politics.html

http://www.planetary.org/blogs/casey-dreier/2014/0314-official-statement-on-nasas-2015-budget.html

http://www.slate.com/articles/health_and_science/mysteries_of_the_universe/2014/02/nasa_s_mission_its_search_for_meaning_has_limited_its_science_and_damaged.2.html

The text was extremely vague on the processes of supermassive black holes. After a little more research, it is clear that this field remains very speculative,although there are some intriguing possibilities.

Image Source: Wikimedia Commons

The most prevalent theory states that supermassive black holes are the product of the collision of primordial black holes. These black holes formed shortly after the Big Bang due to the extremely high pressures. Two black holes and their accompanying galaxies then would have collided, forming some sort of binary system pulling in matter from the surrounding space. This amount of mass would exceed any sort of pressure limits and form one supermassive black hole. This theory is often preferred due to the fact that it explains the relative lack of intermediate-mass black holes. There are many stellar-mass black holes, which form as a result of core collapse. These are on the order of 3-15 solar masses. There are also a high amount of supermassive black holes, which begin around 100,000 solar masses and increase from there. The gap in between the two suggests very different formation patterns, and not a continuous spectrum of constantly added mass that was once imagined.

Image Source: Wikimedia Commons

Astrophysicists have been able to model the collision theory, which lends even more support. But other theoretical explanations abound. The theory of accretion is the most plausible, where a core collapse black hole occurs in a high density region and then forms accretion disks to increase the mass. This theory helps conserve angular momentum, as transfer to gas particles can keep the black hole from spinning too fast and evaporating. However, this does not explain the lack of intermediate-mass black holes. The Laser Interferometer Space Antenna that will hopefully launch in the next twenty years should gather enough data to answer the question of supermassive black hole formation.

Sources and Further Reading:

http://en.wikipedia.org/wiki/Supermassive_black_hole#Formation

http://www.universetoday.com/104044/how-do-black-holes-get-super-massive/

http://www.wired.com/2010/08/massive-black-hole-origin/

There is an interesting conclusion to be drawn from current theoretical physics, and it goes something like this: If the universe is infinite, but there are a finite number of ways for matter to be arranged, then our Earth, with its exact same history, exists in other places in the universe. Not just a few places, but an infinite number of places. This means there are an infinite number of me and you, with an also infinite number of “alternative” versions of us who branch off and make different decisions every second. Pretty crazy, huh?

There are a few things that need to be clarified in this scenario. First of all, even if the universe is infinite in nature, the observable universe is not. We can only observe the parts of the universe from where light has been able to reach us. This observable universe has a calculable volume. One estimate has taken the volume of the universe and divided by the smallest possible quantum length and concluded that there are “only” about 10^180 unique points in the observable universe. An incomprehensibly huge number, yes, but not infinite. So even if there were copies of us somewhere out there, they would truly be existing in an “alternate” universe, unobservable in every way.

Another issue of late has been the shape of the universe. If it folds over on itself like a sphere, it could have infinite pathways to travel without being infinite in volume. Recently, by observing the nature of the cosmic background radiation, NASA’s WMAP project has concluded that the universe is flat to within 0.4%. This leaves the alternative unobservable universes as a possibility.

There are many characteristics of space that challenge the extent of human imagination, but this takes it to another level. If a resolution to this idea is coming, it may be soon as we learn more about the birth of our universe and the Big Bang.

From the time we were first taught about outer space in elementary school, we learned that interstellar space was a vacuum. Basically, we could assume that all mass in the universe was concentrated at stars, planets, or other massive objects while the space between them was a perfectly empty void. While this is a good approximation, it is not entirely accurate.

Our text has made it clear that interstellar space is full of particles and energy, from photons to neutrinos to the interstellar medium to cosmic background radiation. If it did not have any of these things, space would be a perfect vacuum with no energy, stuck at absolute zero (0K). However, this is not the case. Even in the regions of space furthest from any heat sources, the cosmic background radiation keeps interstellar space at a temperature of about 3K. This only increases as we move toward stars, meaning there must be massive particles in space.

But how many? The most widely accepted figure for the density of interstellar space (M. Tadokoro, 1968) is calculated to be 7 x 10^-29 grams per cubic centimeter, which translates to about 40 hydrogen atoms per cubic meter. The best vacuum ever constructed on Earth was done at CERN at reported to achieve a density of about 1000 atoms per cubic centimeter. While this is astonishingly low, it is still over 2 million times more dense than interstellar space! No, space is not a perfect vacuum, but it is certainly the best approximation that exists.

Sources and Further Reading:

http://en.wikipedia.org/wiki/Vacuum#Outer_space

http://adsabs.harvard.edu/abs/1968PASJ…20..230T

http://www.ccmr.cornell.edu/education/ask/?quid=1026

Our reading today mentioned the ultimate fate of nearly all main sequence stars. At the end of the white dwarf stage, the star cools and begins to crystallize. The star, made almost entirely of carbon and oxygen, crystallizes first at the core and eventually becomes a “cold, dark, Earth-size sphere of crystallized carbon and oxygen floating through the depths of space” (Carroll and Ostlie, p. 576). However, the text was unclear about the abundance of these floating diamonds. My understanding was that it takes so long for the cooling process to occur that none of these objects exist yet. This is not necessarily the case.

First of all, a fully crystallized star would emit little to no radiation whatsoever. As such, they would be nearly impossible to detect with modern technology. The only technique that seems plausible for detection is if a crystallized star was part of a binary system so it would cause some wobble in a brighter star. Even in that case, a crystallized star would be indistinguishable from an exoplanet.

Image Source: Harvard-Smithsonian Center for Astrophysics

Fortunately, between 1995 and 2004 a star was detected 50 light-years from Earth that pulsated and had a low luminosity, both signals of a crystallizing star. It was finally determined that between 80 and 90 percent of the star’s mass has crystallized, meaning it still emits just enough radiation to be detected. The final 10 percent will still take many millions of years to completely crystallize, but as is the star has been nicknamed “Lucy” after its diamond-like qualities. Estimations set the diamond in the core of the star at an amazing 10 billion trillion trillion carats! As our technology improves, it is likely that we will detect even more of these massive diamonds.

Sources and Further Reading:

http://en.wikipedia.org/wiki/BPM_37093

http://www.spacetoday.org/DeepSpace/Stars/WhiteDwarfs/LucyDiamondStarWhiteDwarf.html

http://starryskies.com/articles/2004/02/diamond.html

Our textbook reading for today made supernovae sound like some of the most exciting natural phenomena humans have ever observed. A star shining so brightly that it is visible during the daytime is almost unfathomable. I immediately began trying to figure out if a supernova would be visible from Earth during my lifetime. Supernovae are detected often in other galaxies, and a supernova in a neighboring galaxy such as Andromeda would definitely be visible to the naked eye. But for maximum effect, I am most curious about a supernova in our galaxy.

According to the textbook, the last supernova to occur in the Milky Way galaxy was of η Carinae beginning in 1837 and fluctuating in brightness for twenty years. Also, the textbook states that supernovae occur (on average) once every hundred years in any one galaxy. With the last supernova occurring 177 years ago, it sounds like we are long overdue!!

Image Source: annesastronomynews.com/photo-gallery-ii/

Researchers agree with that sentiment. According to a probabilistic model constructed at The Ohio State University, there is nearly a 100% chance that a supernova will occur in the Milky Way within the next 50 years. Unfortunately, they concluded that there is only a 10-50% chance (dependent on the observer’s location on the Earth’s surface and the position of the supernova in the sky) that it will be visible from Earth. A visible supernova in my lifetime is not the foregone conclusion that one might expect, but is certainly still an exciting possibility.

Sources and Further Reading:

http://researchnews.osu.edu/archive/supernova50.htm

http://scienceblogs.com/startswithabang/2012/01/26/our-galaxys-next-supernova/

One of the most well known Bible passages is God’s promise to Abraham, which reads: “ I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore.” -Genesis 22:17 (NIV). While sitting on the beach over spring break, I wondered which of those two quantities was larger.

According to modern astronomers, it is possible to estimate the number of stars in the universe to within at least a few orders of magnitude. By taking the number of stars in our galaxy (somewhere between 10^11 and 10^12) and multiplying by the number of galaxies (another 10^12), it can be estimated that there are somewhere on the order of 10^24 stars in the observable universe. Obviously, this is a very rough estimate, but this is the best estimate available and definitely seems reasonable.

Surprisingly, we know far less about the number of grains of sand on our own planet. Researchers in Hawaii supposedly took the number of grains in a teaspoon of sand and used satellite imagery of the Earth’s surface to estimate the volume of sand on the face on the Earth. They came up with about 10^19 grains of sand. I could not find their methodology posted anywhere, but this seems like a very low estimate for a number of reasons. For one, there is no way to estimate the depth of sand from satellite imagery. Giant dunes in the Sahara obviously contain more sand than a comparable surface area in a sandbox. Furthermore, they say that they only used beaches and deserts in their estimation. I would propose that there are MANY more areas for sand to exist (the floor of the ocean being the greatest omission).

Of course, God’s promise to Abraham specified only sand on the seashore. Either way, I think there is still some work to be done before answering this age-old question.

Sources and Further Reading:

http://www.npr.org/blogs/krulwich/2012/09/17/161096233/which-is-greater-the-number-of-sand-grains-on-earth-or-stars-in-the-sky

http://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe

The power of stars and constellations to capture the human imagination has persisted throughout history. While our means of deciphering the celestial sphere has changed, the sensation of staring into the night sky and pondering our existence among the vastness of the universe has been shared across time and culture. Nowadays, it is essentially effortless to download an app to learn the constellations or use computer software to pinpoint the next eclipse. However, before the advent of such technology as Newtonian physics and the telescope, detailed records of the heavenly bodies were much harder to procure. Remarkably, despite the obstacles to compiling these records, many ancient civilizations made precise astronomy a priority.

El Castillo at Chichen Itza – Image Source: http://www.world-mysteries.com/chichen_kukulcan.htm

The development of the field of archaeoastronomy has rapidly advanced since the 1960s, when Stonehenge was proposed as a monument to astronomical alignment. The number of studies on sites across the world exploded, with many researchers publishing positive results. It is now clear that civilizations on every continent across centuries of human history maintained rigorous observation of stars and planets. The evidence was left primarily in architecture, which unmistakably honors their discoveries.

Newgrange Tomb, Ireland – Image Source: Steve Emerson

Maybe the most impressive aspect of the archaeoastronomical discoveries is the fact that today the stars are not necessarily observed in the same position as they were when these monuments were built. Due to the proper motion of stars and the precession of Earth’s axis. Archaeoastronomers have to account for this and calculate those positions retroactively.

Personally, the most fascinating realization about this field is that these civilizations had no known communication with each other. Independently, indigenous peoples arrived at the conclusion that their position in the universe was of utmost importance, and worth devoting unmatched time and resources to. That is a noble pursuit that continues to this day.

Sources and Further Reading:

http://en.wikipedia.org/wiki/Archaeoastronomy

http://www.archaeoastronomy.com/

One of the sections in our assigned reading tonight covered extrasolar planets. It reminded me about HD 189733b, an extrasolar planet I researched during first block, and one of the wildest things I’ve learned about at any level of physics.

Image Source: Wikimedia Commons

HD 189733b was discovered in 2005, orbiting its host star about 63 light years away from Earth. Using the Hubble Space Telescope to conduct spectroscopy on the exoplanet, researchers determined the planet to be blue, since a drop in blue light was detected whenever HD 189733b would pass in front of the host star. Naturally, a blue planet draws comparisons to Earth, but nothing else about the two planets are remotely comparable.

Image Source: http://chandra.harvard.edu/photo/2013/hd189733/

For starters, the blue color comes not from water, but from a high concentration of silicate in the atmosphere. Furthermore, HD 189733b does not spin about its axis, so there is no day and night. The side facing the host star cooks perpetually at a temperature around 1800°F, baking the silicate into a molten glass cloud straight out of a sci-fi movie. Since the dark side never receives any heat, the vast temperature differences result in incomprehensible wind speeds exceeding 4000 MPH, whipping the molten glass across the planet’s surface

It is safe to say that HD 189733b does not support the alien life that many humans are obsessively searching for. However, the detail to which astronomers have been able to discern the activity on the surface of this planet should be encouraging to anyone interested in the exploration of outer space.

Sources and Further Reading:

http://www.nasa.gov/content/nasa-hubble-finds-a-true-blue-planet/#.UzI7EYVTry0

http://en.wikipedia.org/wiki/HD_189733_b

http://www.space.com/22614-blue-alien-planet-glass-rain.html