Gravitational Waves and Extra Dimensions

Posted on February 13, 2018 by stellarastronomy1995

The existence of dimensions beyond the three spatial and one temporal we experientially inhabit in our current model of spacetime has been a longstanding discussion touched on by various physicists and the scientific community. It has been suggested that gravity would propagate throughout these other dimensions, a thought brought about in attempts to somewhat unify aspects of quantum theory and general relativity, and explain the apparent “weakness” of gravity. The detection and measurement of gravitational waves paved the way for last year’s proposal that anomalies in detected gravitational waves could suggest the existence of extra dimensions. Given the assumption that gravity interacts with extra dimensions, gravitational waves would similarly interact with these dimensions were they to be present. The idea is that if there are extra dimensions that gravitational waves are interacting with, this interaction would be a detectable phenomena by means of calculating the anticipated strength of the waves given their source and their strength once they reach the detector. An unexpected measurement in the strength of the gravitational waves would provide evidence for extra dimensions “stealing” and therefore weakening the waves over distance.

gravitational_waves_fig1
As gravitational waves propagate through spacetime, they expand and contract space like a rubber band being stretched and returned to its natural shape. The wavelengths of these waves are immense, with those generated by the blackhole merger to be 15,000 km (also link to image). 

This hypothesis was promising, however earlier this year observations from two colliding neutron stars were used to compare expected and measured strengths of gravitational waves in search of and leakage that would have occurred, causing a reduction in wave amplitude. The strength of detected gravitational waves given their distance was as expected, meaning no measured leaking took place to suggest the presence of large extra dimensions. Despite this result, there still remain extra-dimensional theories to be tested.

For more information on the significant connection between the strength of gravity (mainly how weak it is) and the possibility of extra dimensions, I found this video to be extremely informative and easy to understand.

Featured image: Artist Penelope Cowley’s rendition of gravitational waves

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Light – Beyond the Shadow

Posted on February 13, 2018 by stellarastronomy1995
Scientists-discover-new-form-of-light
Artist’s Rendition of Photons with Angular Momentum

 

Plato believed that our senses could not be trusted to reveal the truth of the Universe. He argued that the world around us was an imperfect representation of the ideal world, our perception put before us by our faculties – simply shadows cast from imperceptible forms. Cognizance of truth was achievable only by means of reasoning through the employment of one’s intellect.

The thought of being unable to trust one’s senses to show the truth of reality was suggested to result in the death of the philosopher. People do not want to hear that they have been living a lie, that everything they know is not the true nature of reality. The upheaval of one’s beliefs, identity, and entire worldview must cause them strife, anger, and lead to violent opposition and denial, according to Plato’s writings. However behind our perception of reality, the search for the true nature of the Universe and the pursuit of science is for the most part now welcomed with excitement and wonder. The abstract nature of light brings some truth to Plato’s fundamental belief. While most are familiar with the what light does in their daily interaction with it, our perception alone by our senses does not bring us to a full understanding of the truth. While early thinkers believed sight was the product of our eyes emitting rays which bounced off those things looked at and returned to us, our modern understanding of light reveals it as information carried by electromagnetic energy. Exhibiting properties of both a wave and a particle, photons are packages of light that carry radiative energy and are characterized as waves are, by wavelength and frequency. Visible light is only a small fraction of the information carried in the electromagnetic spectrum, and it is easy to see how ignorance of this would lead to the conclusion that the light we perceive through our senses is all there is. However there is a vast field of information all around us and throughout the Universe that we are unable to detect without the aid of modern instruments. To fully understand the nature of the Universe, the capacity to recognize, receive, and decipher the ways in which it communicates information to us in its entirety is essential.

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A Greedy, Gluttonous Galaxy

Posted on February 13, 2018 by terranojm

It’s no secret that the universe is growing. However, research leads us to believe that our own Milky Way Galaxy is growing as well. In fact, our galaxy exhibits cannibalistic behavior, absorbing material from the dwarf galaxies surrounding it. We know that the chemical makeup in the central bulge of our galaxy differs from the chemical makeup of the outer halo of our galaxy, and we have also found that the chemical makeup of the outer halo of our galaxy is similar to the chemical makeup of stars found in dwarf galaxies orbiting our galaxy – namely, the Large Magellanic Cloud and the Sagittarius Dwarf Elliptical Galaxy. Therefore, these dwarf galaxies may simply be the leftovers of galaxies that were long ago absorbed into our own galaxy.

milkywayside1

Milky Way Galaxy

Astronomers believe the key to understanding the growth of our galaxy is learning more about the dark matter around our galaxy. The halo of dark matter surrounding our galaxy actually exerts a gravitational force on smaller, neighboring galaxies, so it may be that dark matter is ripping away stars and pulling them into the external regions of our galaxy. There are still so many unanswered questions about dark matter and dark energy, but a project called the Dark Energy Survey is currently underway, in which we are using a tool called the Dark Energy Camera to detect stellar streams. Stellar streams are groups of relatively few stars that have been ripped away. They are difficult to detect because we are looking for a small number of stars in such a large region of space. Nevertheless, these stellar streams illustrate how our galaxy is constructed from smaller galaxies, so the future findings of the Dark Energy Survey should prove exciting!

 

Links:

http://www.astronomy.com/news/2018/02/did-the-milky-way-devour-other-galaxies-to-grow

http://www.futurity.org/milky-way-stellar-streams-1653962/

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Just Because You’re Bulkier, Doesn’t Mean You Pull More

Posted on February 13, 2018 by jonahastroblog

We’ve all seen and learned about the cosmos and the stars up above. We learned that the Earth revolves around the Sun because the Sun’s force on the Earth is greater than any of the other major celestial bodies near this. However, something that many people forget is that this process is facilitated by Newton’s Universal Law of Gravitation.

In terms of the realm of physics, Newton describes the Universal Law of Gravitation as:

F12 = G$\displaystyle{m_1 m_2 \over r^2}$

Now, I understand that the physics formulas can be a bit daunting, so let is break this down. First, let us define the variables in this formula:

F12 = Force exerted by one body on another

G = The Gravitational Constant (for those technically inclined, this number is 6.67408 × 10-11 m3 kg-1 s-2)

m1= Mass of one of the bodies

m2= Mass of the other body

r2= distances between the center of each body, squared

Okay, so now that we know what the equation means you’re probably asking

“Okay, so now I know how the force between two bodies is measured. What does that have to do with anything?”

Well, this is important because this clears up a common misconception in people’s minds about gravity and attraction, especially in space. Let us say that, for example, m1 is the mass of the Earth, m2 is the mass of the Sun, and r is the distance between the sun and the Earth. Then, our Law of Gravitation Equation would look something like this:

Gravitation1

This formula is then saying that, if we had all of these values, then we would know the gravitational force that the Earth exerts on the Sun. Now, let’s switch it around. Let’s say m1 is the mass of the Sun, m2 is the mass of the Earth, and r is STILL the distance between the sun and the Earth (in other words, r has NOT changed). Then, the force that the Sun exerts on the Earth would be characterized by:

Gravitation2

Now, if we employ our first grade multiplication rules (the Commutative Property of Multiplication), we notice that both forces are equal! Yes, this means that the force that the Sun exerts on the Earth is EQUAL to the force the Earth exerts on the Sun. This is important because it proves false the common misconception that more massive things pull stronger on an object than less massive things. We see that, by using the Universal Law of Gravitation, this is false. Therefore, we can conclude that all objects that attract each other exert an equal force on one another.

Now, this also generalizes to smaller objects as well. Yes, humans have a gravitational attraction to their phones just as their phones are gravitationally attracted to them. However, the force of this attraction is so weak that we simply do not notice it. This Veritasium video does well in explaining the mathematics behind this. However, now that you know this this means that the pasta you attracted toward your face for dinner had an equal gravitational attraction to you. And, for those of you looking for a Valentine, you can now be certain that your crush is equally attracted to you as you are to him or her (at least concerning gravitational attraction).

love
Sourced from theodysseyonline

Featured Image Sourced From ytimg

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NASA Cuts and Privatizing Space – Trump’s Plan

Posted on February 13, 2018 by lexisastronomyblog

The Trump administration’s NASA budget request for 2019 was revealed today, and many of the requests come at the dismay of many prominent people in the space and astronomy field. Most of the requests call for NASA to pursue commercial partnerships. For example, the administration requests NASA stop directly funding the International Space Station (ISS) by 2025, urging them to find commercial partnerships with private companies and other countries to fund the satellite. The budget allocates an extra $150 million to NASA to start a program to get more commercial companies involved in low orbit Earth projects. Many have spoken about the funding cuts of the ISS, saying that America should not leave its main post in space as the boundaries of our knowledge of space are being pushed.

iss
International Space Station via The New Daily

The Trump administration also wants NASA to focus on sending humans back to the Moon. However, the budget does not allocate enough funds or detail enough plans to make lunar ambitions feasible at this point. Instead, the budget again requests that NASA look toward commercial rockets for moon landings and other projects. While focusing on sending humans back to the Moon, the administration requests the shutdown of five Earth Science missions, one of which is the WFIRST telescope. This telescope gives scientists the ability to study dark matter and exoplanets. NASA’s Education program, which funds grants and scholarships for students, is also on the chopping block. The budget requests that this sector be completely cut, but Congress defied this request last year, making sure the program still received funding. We will have to stay tuned to see what components of this budget actually get confirmed.

The privatization of space missions is a multifaceted problem. Privatizing something means that the people investing in said thing would need a way to gather profit. When dealing with a thing such as space, where is there a profit to be made? Space exploration is done because people believe it is a necessary good. As humans, we are naturally curious and want to know more about the space we inhabit. By privatizing explorations, companies could essentially restrict what is being learned and who is learning it. As the budget is reviewed and finalized, I hope people will see the many caveats of turning space into a private venture.

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NASA Cuts and Privatizing Space – Trump’s Plan

Posted on February 13, 2018 by lexisastronomyblog

The Trump administration’s NASA budget request for 2019 was revealed today, and many of the requests come at the dismay of many prominent people in the space and astronomy field. Most of the requests call for NASA to pursue commercial partnerships. For example, the administration requests NASA stop directly funding the International Space Station (ISS) by 2025, urging them to find commercial partnerships with private companies and other countries to fund the satellite. The budget allocates an extra $150 million to NASA to start a program to get more commercial companies involved in low orbit Earth projects. Many have spoken about the funding cuts of the ISS, saying that America should not leave its main post in space as the boundaries of our knowledge of space are being pushed.

iss
International Space Station via The New Daily

The Trump administration also wants NASA to focus on sending humans back to the Moon. However, the budget does not allocate enough funds or detail enough plans to make lunar ambitions feasible at this point. Instead, the budget again requests that NASA look toward commercial rockets for moon landings and other projects. While focusing on sending humans back to the Moon, the administration requests the shutdown of five Earth Science missions, one of which is the WFIRST telescope. This telescope gives scientists the ability to study dark matter and exoplanets. NASA’s Education program, which funds grants and scholarships for students, is also on the chopping block. The budget requests that this sector be completely cut, but Congress defied this request last year, making sure the program still received funding. We will have to stay tuned to see what components of this budget actually get confirmed.

The privatization of space missions is a multifaceted problem. Privatizing something means that the people investing in said thing would need a way to gather profit. When dealing with a thing such as space, where is there a profit to be made? Space exploration is done because people believe it is a necessary good. As humans, we are naturally curious and want to know more about the space we inhabit. By privatizing explorations, companies could essentially restrict what is being learned and who is learning it. As the budget is reviewed and finalized, I hope people will see the many caveats of turning space into a private venture.

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Red, White, and Blue: The Star Life Cycle

Posted on February 13, 2018 by mattbarnhartastro2110

We’ve talked a bit about black body radiation and how some stars appear more reddish or bluish, or maybe even just white. But how  and why do stars appear as more reddish or bluish, and why are some stars larger than others? What makes Red Giants and White Dwarfs special? Well, it all has to do with the life cycle of stars as they burn through the Hydrogen and eventually other fused elements that make them up  (around this time they become Red Giants) until they run out of fulifestarsel and either disspate into a White Dwarf surrounded by a planetary nebula or explode in  supernova and either become Neutron Stars or, in the case of extremely large stars, black holes.

We know even more about stars than just their life cycles though – Ejnar Hertzsprung and Henry Norris Russell worked in parallel studying dwarf and giant stars, determining that there was a relationship between the mass and luminosity of a star and its color. This research was later used in the creation of the modern Hertzsprung-Russell Diagram, which plots stars according to their temperature and luminosity relative to the sun.labeledHR

Stars in the Main Sequence are generally in the process of fusing their supply of Hydrogen. Stars on the Main Sequence range from Red Dwarfs, which fuse hyodren extremely slowly and are expected to stay on the main sequence for about 2.5 trillion years before becoming blue dwarfs. Massive stars on the Main Sequence are generally blue, while stars like the Sun waver in the middle of the main Sequence and emitting white light. Stars that are less than a quarter the sun’s mass will die peacefully by turning into white dwarfs, while more massive stars will turn into dimmer but larger Red Dwarfs. Stars much larger than the sun, such as Blue Giants, get their color from their extreme temperature compared to the sun.

 

Sources:

Space.com: Main Sequence Stars

Wikipedia, “Main Sequence”

School Observatory, “Life Cycle of a Star”

Astro Keele, “The Life of a Star”

What I vaguely remember of the IB Physics Astronomy unit

 

 

 

 

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Crop Circles: A Brief History

Posted on February 13, 2018 by Jeanie Zeng

Crop circles have long captivated the attention of conspiracists. Their theories suggest that they appear within hours and during daytime without forewarning or even observation of their creators. Modern-day conspiracists have often pointed to them as evidence of the supernatural or more recently, extraterrestrial communication.

The idea is that aliens have used beams from their spaceships or other structures to physically carve these crop circles into fields. UFOligists often point to crop circles as evidence of extraterrestrial communication.

Image result for crop circle aliens

Crop circles have an unclear origin. The earliest reported sighting appears to be a news pamphlet from 1678 that discusses the Mowing Devil. This was the figure who was supposedly responsible for the inhumanly perfect mowing work performed on a farmer’s crop field after the farmer claimed he would rather have the devil mow his field than pay a laborer to do it. Even this source, however, contradicts the theories presented by modern-day crop circle enthusiasts, as the enthusiasts point to crops being bent whereas the Mowing Devil myth indicates that the crops were cut.

It was really only in the 1970’s when the idea of crop circles really began to take form. In 1996 in the England countryside, one of the most famous crop circles appeared near the Stonehenge monument, a structure already shrouded in mystery. This specific crop circle  (pictured below) was especially unique due to its clearly deliberate and intelligent construction. This was a stark contrast to previous crop circles which were easily attributed to nature. Like many cases to follow, it was later discovered that three people had been playing a hoax.

To date, just over 10,000 crop circles have been reported around the globe. Like the one that appeared near Stonehenge, all have been found to have been caused by hoaxers or originate from natural sources. Nevertheless, the idea of extraterrestrial life and our communication continues to fascinate us. Centuries later, we are still searching for signs of this communication.

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European-Extremely Large Telescope

Posted on February 13, 2018 by terranojm

The European Southern Observatory began construction of the European-Extremely Large Telescope (E-ELT) back in 2014. This telescope is on track to be the world’s largest optical and infrared telescope by the time it is completed in 2024, thus living up to its name. The E-ELT will include a main mirror that is 128 feet in diameter, beating out some of its competitors, such as the Giant Magellan Telescope and the Thirty Meter Telescope, which boast main mirrors that are 82 feet and 98 feet in diameter respectively. This telescope will be able to capture images 16 times sharper than images captured by the Hubble Space Telescope.

The E-ELT will be used to study exoplanets, dark matter, supermassive black holes, galaxy formation in the early universe, and much more. Observations from this telescope may be able to answer questions such as if the laws of nature really are universal, and we may be able to learn more about stellar populations at distances of tens of millions of light-years away from us. The E-ELT will be operating in northern Chile’s Atacama Desert, an ideal location for astronomical observation due to the dryness of the air and the clarity of the night sky. However, Chile, like most other locations in the world, still suffers from light pollution, so efforts to limit blue light emissions and luminous signs have come about.

Astronomers hope the E-ELT will be in use for at least 30 years. At a price of $1.4 billion, I would sure hope so. The more technology advances, the more we will be able to learn about our universe. The farther distances we will be able to look out to, and the more we will be able to essentially look back in time. I’m excited for the astronomical discoveries bound to emerge. However, given the fact that we have just over six and a half years left until the E-ELT’s first light, we’ll just have to be patient for now!

e-elt_compared_to_big_ben_2000z1180

E-ELT

 

Links:

https://www.forbes.com/sites/brucedorminey/2018/01/31/chiles-pristine-skies-are-key-to-astronomys-next-generation-of-telescopes/#d9489c32dcf8

https://newatlas.com/extremely-large-telescope-construction-begins/49747/

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Radio Telescopes

Posted on February 12, 2018 by mattbarnhartastro2110

When someone says “telescope,” you probably think of a long magnifying tube ranging from pocket sized to massive that you can look in an eyepiece of to see things at great distances, such as stars and galaxies in regards to astronomy. Another type of telescope you may not think of is the radio telescope. The Greenbank Observatory (formally the National Radio Astronomy Observatory) in West Virginia is a site for some of these radio telescopes, especially the Greenbank Telescope, the world’s largest fully steerable radio telescope with a dish that is 100 by 110 meters.

GBT

The GBT’s off-axis parabolic segment dish to reflect light into the focal point slightly to the side, where data is collected electronically.
The GBT isn’t the only radio telescope at the Greenbank Observatory. When I visited last year with my IB Physics class for an observation project, we got to use the 40 foot telescope on-site to observe specific astronomical objects and to collect data to understand how we understand the structure of the Milky Way. 40ft

While the 40 foot must be operated on-site due to the old technology for controlling it and collecting data, the 20 meter telescope can be used remotely by anyone for education or research by applying through the UNC Skynet Program.20m

Sources:
Greenbank Observatory Site

NRAO Site (old site, used for images)

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