About Tides

Posted on February 18, 2013 by gerretyc

Upon beginning this course, I knew that the tides had something to do with the Moon and gravity, but I really didn’t understand exactly what was occurring.  I was under the impression that since water moved more readily than land, that tides could be explained by the Moon’s pull on the water.  However, what I did not realize was that it is the difference between the gravitational pull of the Moon on either side of the Earth that causes the tides, and that this difference causes the Earth itself to stretch, rather than just the water on its surface.  Furthermore, I did not realize that the Sun affected the tides as well.

Spring tides occur as a result of the Moon and the Sun acting together to pull on the Earth, while neap tides occur as a result of the Moon and the Sun counteracting one another.  However, the Moon’s effect is much stronger because, despite the fact that the Moon is significantly less massive than the Sun, the Moon is closer to Earth.


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Space Shuttle Resting Spots

Posted on February 18, 2013 by kevinm387

Space Shuttle Resting Spots

Above is a photo of the shuttle Endeavor flying over my hometown, Houston, before it retired. The final resting spots for these shuttles included Los Angeles, New York City, the Kennedy Space Center in Florida, and the Smithsonian in Washington, D.C. As you can see, Houston was not included as one of the final destinations for these shuttles.

Pardon me in advance, because I am about to go on a rant. How in the world did Houston not get one of these shuttles?! Houston’s official nickname is “Space City”! Upon landing on the Moon, Neil Armstrong’s first words were, “Houston, Tranquility Base here. The Eagle has landed.” The first word radioed back from the Moon was “Houston”! It was scientists at mission control at the Johnson Space Center in Houston who made sure the Apollo 13 crew members survived and returned home safely. Houston has a richer history relating space than any other city in the nation, maybe even the world. The Johnson Space Center has always been NASA headquarters and would be the perfect resting spot for one of these shuttles. Instead, Houston got the consolation prize: the replica shuttle Explorer that was never operational.

It is a complete travesty that Houston was denied a space shuttle in favor of, say, New York City which has had practically nothing to do with NASA or space. These decisions were made based solely on politics and not on merit, which is a shame. I feel bad for Houston residents who have worked at the Johnson Space Center, especially those who worked at mission control during these shuttles’ flights.

Here is the link to the photo above.

And for those interested, here is a Houston Chronicle article about how partisan politics probably affected the decision to exclude Houston.


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James Webb Space Telescope

Posted on February 18, 2013 by juliettealper

Image

universetoday.com

The James Webb Space Telescope (JWST) is Hubble’s successor. As impressive and useful as Hubble was, it will eventually stop working and spin out of it’s orbit. That is why the JWST is being made. It will be better and more advanced than Hubble, allowing scientists to view infrared light. JWST will study four main questions: one regarding what happened right after the Big Bang, another discovering how galaxies are formed, then the birth of stars and protoplanets, and lastly information on the origin of life. Clearly this telescope is going to be extremely important, which is why NASA and scientists pushed so hard for it’s creation.

The original plan was going to have the JWST ready by 2007, spending 500 million dollars. Of course, what was projected is much different than what actually happened. People disagree upon why the project is now expected to be ready in 2018, over ten years past the expected date, and costs 8.8 billion dollars. Some say it was poor management on the project, but others say that of course there will be technical issues and surprises when building a brand new robot. Whatever the issue, I personally think it will be worth it. This telescope, if successful, will give us so much new information about the universe- I can’t wait to see what happens.

Sources:

http://news.yahoo.com/

http://www.jwst.nasa.gov

I wrote a feature article about the JWST for a class last year, if you want to get more in depth!

http://jalper.tumblr.com/


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Virgin Galactic

Posted on February 18, 2013 by indianwm

Sir Richard Branson of Virgin records, Virgin mobile, and many other large companies has brought the dream of space travel to civilians. Finally, non-astronauts are able to roam through space and experience what very few have. This trip, however, is quite expensive and will not be able to be experienced by everyone. The starting price of this once in a lifetime experience is $200,000 with a $20,000 deposit. Needless to say, this is still reserved for only few who are able to afford this. The price may seem outrageous, but when looking at what goes into the process, it makes a little more sense. There is a large spacecraft that carries the passenger spacecraft into space. These were both designed with state of the art technology. There is also the $200 million spaceport that sits on 27 square miles of land. So in order to make this feasible, trips were not going to be cheap.
The Spacecraft that carries the passengers is the SpaceShipTwo. It carries 6 passengers and is powered by a hybrid rocket motor. The Ship that carries the SpaceShipTwo to its altitude is the WhiteKnightTwo. This can reach speeds up to 2500mph or three times the speed of light and can carry a payload of 35,000lbs.
The experience of this flight is like nothing else. Once the SpaceShipTwo reaches its highest altitude, the motor is shut down where the silence of space is felt throughout the cabin. Then, you are hit with the feeling of weightlessness where no gravity constrains you. If you wish, you may leave your seat and float around as we have seen astronauts do so many times before. Next, you are face to face with a large window where you see earth as only a privileged few have seen it before. Then is the decent back into the atmosphere and landing back at the spaceport. This flight is the ultimate experience that will change your view on life and space forever.

Virgin Galactic


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The Hubble Telescope

Posted on February 18, 2013 by williamcpower

After reading about the power of different telescopes, I became interested in learning more about the famous Hubble Telescope. I found a video that explains some of the telescope’s mechanics and I think it’s worth the watch. What is really fascinating is the sensitivity the Hubble Telescope has. It can detect a candle from Tokyo from a distance as far away as Los Angeles. It is able to do this because it is a reflector telescope. It reflects light of many mirrors in order to magnify and focus it. Watch the video to get a better idea of how this works watch the video. It takes incredible precision in order to achieve this. When the telescope first when up, the primary mirror was off by about 1/50 the thickness of a human hair. This was enough of a defect to cause a blurry image. An interesting history about all the logistics of setting the telescope up can be found here at howstuffworks.com

Image

Picture from NASA


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Navigation by the Stars

Posted on February 18, 2013 by jhughes216

History

Before the time of GPS devices, navigation apps, and even before the Earth was known to be round, humans were using the heavens to find their way around this hardly discovered planet. While land navigation could be made fairly easy by dead reckoning and using landmarks, this technique became infinitely more difficult once humans began to traverse the uncharted oceans.

While the Europeans had compasses and experience charting maps to help them use dead reckoning techniques, the Vikings relied more on the Sun and stars to plot their journeys over the Atlantic. Without the help of tools and calculations for navigation, the Vikings began using the position of the North Star and the Sun to keep track of their latitude on the open sea. This way, they were able to sail north and south along the coast to their desired latitude and then just keep a constant baring east and west.

The arabs, who were profoundly active in astronomy around the same time, began to use celestial navigation in the same way and eventually developed various tools to aid with this. These tools and techniques found their way to Europeans who expanded on their ideas and eventually created the sextant, a device that allows one to accurately measure the latitude of his or her position.

Today

Recent development of satellites that help track position and other such tools have begun to make celestial navigation obsolete. Even still, most experienced sailors know that relying on any one tool to help you navigate can lead to terrible situations if that one tool has a failure. For this reason, sextant navigation is still being taught at major naval military academies all over the world. In less practical usage, many casual sea travelers still enjoy the using the sextant  as it seems a more pure and honored way to navigate.

Conclusion

Stars were the building blocks to modern navigation. In a time when humans relished in studying the heavens, they were able to plot the course of the stars and accurately use them to navigate an unknown world. While the method may be somewhat outdated in this age of technology, it is still a true testament to the incredible things we can discover about our own planet through the use of the universe and its contents.


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The Hubble Telescope

Posted on February 17, 2013 by indianwm

http://images3.wikia.nocookie.net/__cb20120304232460/bigbangtheory/images/3/36/Hubble_in_orbit1.jpg

The Hubble Telescope has been one of the most beneficial tools for discoveries and research since the beginning of the study of astronomy. When the Hubble Telescope was launched in 1990, it was sent 353 miles above earths surface where it would orbit earth at an incredible speed. The telescope orbits earth every 97 minutes. When Hubble was initially sent to space, there was a problem detected with the shape of its mirror. It is a Cassegrain reflector telescope that utilizes multiple mirrors that are able to capture and process much more light than the human eye. Therefore, the improper shape of the mirror was a critical problem that affected the clarity of pictures it was able to take. NASA then sent a space shuttle to repair the mirror. It has since been fixed and is routinely serviced in order to keep its abilities and technology up to date.

The Importance of the Hubble Telescope has been tremendous. The reason that Hubble is superior to other telescopes is due to its operation outside of the earths atmosphere. This limits the capabilities of most ground telescopes because the earths atmosphere blocks and absorbs some different types of radiation that is given off by planets and stars. This is what causes them to twinkle to our eyes. The best way to study and observe these astronomical objects is with their given radiation which will allow us to discover more about it. The Hubble Telescope has thus shown us images that we could not have obtained before. And with these images we have been able to discover many things about the universe. One of these being we now have narrowed the age of the universe greatly to 13-14 billion years. Before Hubble we estimated it anywhere from 10- 20 billion years old. We have also been able to study galaxies, stars, and planets in much greater detail. Therefore, we owe much of our recent astronomical discoveries to the great benefit of the Hubble Telescope.

Hubble Telescope


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The European Extremely Large Telescope

Posted on February 17, 2013 by charlesbcochran

Telescopes are essential for astronomy to progress, as the only information available for this science is the light that the universe provides us. Naturally, it makes sense that being able to see the light from objects as clearly as possible and as distant as possible provides with us with increasingly more knowledge about our universe. Essentially, one of the most foundational parts of a good telescope is simply the sheer size of the telescope. More specifically, the diameter of the light collecting area and the quality of the angular resolution are what define the quality of telescope. Thus it makes sense that through the years telescopes have gotten increasingly larger in order to provide better images of the universe.

It is quite interesting to review the progression of telescopes and how far we have come since Galileo’s invention. Here are a few interesting sites that document this timeline:

Telescope Timeline (National Geographic)

Interactive Timeline (TimeToast)

However, what has really been headline news in astronomy has been the plans for what has been dubbed the European Extremely Large Telescope.

Hence the name, this project is pushing the boundaries of telescopic exploration to a whole new level. This telescope will cost about 1 billion euros, and will feature a primary mirror roughly 42m in diameter! To give some scope (pun intended) to the size of this mirror, Galileo’s first telescope was 3.8 centimeters in diameter.

Additionally, this mirror will be composed of 798 hexagonal segments that will give exceptional image quality.

This telescope is planned to measure several of the most meaningful components of our universe, such as the rate of expansion and the observation of the consistency of our physical principles.

Here is a link to the trailer for this project:

Trailer

Image


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Destination: Black Hole

Posted on February 17, 2013 by ibrahim2016

I like black holes. I like them a lot. They are in the top ten of my bucket list of destinations if I live for a thousand years.

Seems Legit

Seems Legit

Black holes in popular culture are notorious for being very dark objects. I will try enlighten the readers about their shady origins, and hope that people see them in a better light.

Stars run on hydrogen. In the extreme temperatures in their cores, hydrogen nuclei fuse explosively to form helium nuclei. The explosive energy released opposes the force of gravity of the star on itself. Thus the star continues its merry existence, until it runs out of juice, that is. When there is no more hydrogen left to fuse, the temperature at the core decreases, gravity takes over and the star contracts. The contraction again heats up the core to a level where helium fuses into carbon. This reaction is much more powerful than hydrogen fusion, and the explosive output causes the star’s shell to expand, making it a red giant.

If the star is less that 10.5 solar masses then it sheds its outer layers leaving behind a very dense white dwarf star made of oxygen and carbon. the white dwarf star is prevented from collapsing further by the electron degeneracy pressure. However, if the mass of the white dwarf is more than about 1.4 times the mass of the sun, even electron pressure cannot hold back gravity. And so the electrons fuse with protons to become neutrons, thus forming a neutron star. A neutron star achieves stability due to the quantum degeneracy pressure (that particles simply cannot have the same state and so must remain separate).

However, if the mass of the neutron star exceeds 1.5 to 3 solar masses, it collapses again into one of several exotic remnants, one of which is the black hole.

starlife

Source


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Wormholes – Science Fiction May Be Real

Posted on February 16, 2013 by surujdeka

We’ve all seen numerous movies or TV shows with spaceships travelling through what is called a wormhole to emerge on the other side into an alternate universe. Although the idea of these cosmological shortcuts may seem wholly exaggerated, they might actually solve many of the mysteries concerning black holes. For instance, the idea of black holes at present is still not completely understood by physicists and astronomers because some of the postulates about their behavior violate the most fundamental laws of classical and quantum physics. A black hole is supposed to infinitely curve space time so that anything that enters it will keep travelling forever. The idea of infinity just does not sit well with classical physics or mathematics. The more important problem that current theories about black holes promote is the information paradox. That is, if nothing that goes into the black hole comes out, then it must be the case with information too. But the laws of quantum physics forbid information from being erased this way! (just like energy cannot be created or destroyed).

That is where the idea of wormholes comes in handy. Some physicists have started suggesting that if the black holes we observe now are actually wormholes, then both the problems of infinite curvature and loss of information disappear. This is because an object entering a black hole or wormhole would appear on the other side out of a “white hole” into an alternate universe! So the hole does not stretch to infinity and neither is there loss of information.

Of course the question then is how do we distinguish between black holes and these wormholes if they were to exist? The answer is Hawking Radiation, an emission of particles and matter that can only come from a black hole and has a characteristic energy spectrum.

Although these are all speculations now, maybe one day, we will be able to actually send something into a black hole and see if we emerge into a parallel universe through a wormhole!


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