Tennessee Fights Science

http://blogs.discovermagazine.com/badastronomy/2012/03/22/tennessee-legislature-boldly-sets-the-science-clocks-back-150-years/

This is not specifically related to astronomy, but I thought this was really sad. If passed and signed into law, this bill will allow Tennessee teachers to "discuss creationism in the class room, as well as global warming denialism." The war against science in this country has to end. We need to preserve the separation of church and state. Tennessee is trying combat science, which is founded on empirical evidence, with ideas that are based on nonsense. We cannot expect to be successful in the global economy in the 21st century if we do not produce scientists. Hopefully, backwards thinking like this stays in Tennessee.


Here's one of my favorite clips from Family Guy that says it all:

Space X

Space X is a company founded by Elon Musk, a billionaire who made his fortune as an internet entrepreneur (co-founder of PayPal, which he sold to ebay) and is the owner of Tesla Motors, which makes high end electric cars (appropriately named), and SolarCity. I came across this video of an interview with him on 60 minutes. It is quite fascinating. Currently, the U.S. doesn't not have a space shuttle program, which ended last year.


Space X designs rockets and space cargo ships that are set to transport cargo to the space station. The next flight of Space X's Falcon 9 which will carry the Dragon capsule to the space station is scheduled for April 30th.


There is a lot competition by private companies to build NASA's next manned space craft which will fly astronauts to the space station and Elon Musk is very optimistic that Space X will win that contract.


This is very interesting to me because, for one, the U.S. is actually contracting space flight out to private companies, and it it seems to be working! This is exactly what I would do if I had billions of dollars. Who wouldn't want to build space craft! It is a long video, but worth the watch in my opinion.

Elon Musk is a fascinating guy. He has business and physics degrees, dropped out of grad school to star to start an internet company, and later was one of 5 co-founders of PayPal. He is CEO and chief technology officer of Space X, despite not having and aerospace background (he claims to be self taught). Space X was awarded a $1.6 billion from NASA for 12 flights of their Falcon 9 rocket. Musk has business interests the internet, clean energies, and space. He was the inspiration for character Tony Slark (Iron Man) in the Iron Man movies (which I have not seen).

"I think it's important that humanity become a multi-planet species. I think most people would agree that a future where we are a space faring civilization is inspiring and exciting compared with one where we are forever confined to Earth until some eventually extinction event." -Elon Musk

This guy is awesome!

How My Perception of Astronomy Has Changed

After taking Physics 111, my perception of astronomy has changed a little. Before, I thought astronomers just took a lot of cool pictures of the night sky and I didn't give a whole lot of thought to what else with which they occupied their time.


It seems many astronomers have to travel a lot, as they go around the world to various telescopes (that's pretty cool! Free trip to Hawaii for time on Keck? Heck yeah!). Also, the massive collaborations that are going on and the amount of money the world, not just the U.S., investa into this (which is actually not that much, since we spend less on NASA in a year than we spend on air conditioning tents in Afghanistan). Still, the price tags are amazing to a college student living off hot dogs and noodles. Overall, astronomy feels like a lot bigger a field than it did before.


Another thing is, the textbook for an intro astronomy class is intimidating with all its equations! I can't imagine how bad it gets in graduate school and with special relativity. It's a good thing we got an equation sheet for our tests, and that covers probably less than a percent of one percent of the equations in the book. So what I'm trying to say is, we know a lot more about the Universe than I thought we did.
Yet with evidence of dark energy and dark matter, the accelerating universe, and brown dwarfs (and much, much more), there are still many discoveries being made and new questions arising that need answers.

Scientists Use Same Method We Used on Homework to Find Diameter of Sun

It is not as though I expected the calculations we do on our homework to be different from the way astronomers really solve problems (I did get a feeling that Prof. Siana wrote the homework so that we got a feel for the way astronomers actually figure these things out), but I was a bit surprised that a method we used to solve a problem was used so recently on something that I would think would have been well documented for some time. It turns out that measurement of the diameter of the Sun are much harder to make than one might think. For one thing, we are looking through our atmosphere and have the problem of seeing if we make the measurement from Earth. Also, telescopes are hard to calibrate in order to measure the Sun with such great accuracy as was obtained using our simple homework problem method.

If you recall, on homework assignment 5, we used data from the Kepler spacecraft to measure the diameter of a star with an orbiting planet. This is what astronomers did using SOHO (Solar and Heliospheric Observatory), a telescope fixed in orbit around the Sun at L1 (the 1st Lagrangian point). Now, there is a slight difference in the ways these two different telescopes made these measurements. The Kepler measurement of the distant star was based on flux, white the SOHO measurement is based on taking images and being able to actually see the planet, in this case Mercury.

Now, even though we have known to great accuracy the diameter of the Sun for some time, this new measurement is the most accurate to date. The Sun is 1,392,684 +/- 65 km in diameter. This equates to an accuracy of 99.995%!

Now you may notice from this picture that the line Mercury traces out is not the diameter. An easy fix! The time Mercury was in front of the Sun was measured to an accuracy to within 3 seconds and to within 1 second, in two different years. This combined with Mercury's well known orbit and some simple trig, figuring out the diameter was not hard.


For more information, follow the Bad Astronomy link from our Phys 111 blog home page or go to:

http://blogs.discovermagazine.com/badastronomy/2012/03/21/the-sun-is-1392684-65-km-across/

Bad Astronomy by Reporter

PTF-11kly, a supernova which was visible from late August through mid September of last year, occurred 21 million years ago in the Pinwheel Galaxy. This supernova was the closet Type Ia to be seen in the last 25 years. Type Ia supernovae are very important to astronomers because they act as standard candles in determining distances to objects very far away. Of course, the distance to the Pinwheel Galaxy, a face on spiral galaxy, has been known for a very long time. The reason for this post is in watching a news report on this supernova I came across some bad astronomy. The following video came from a Fox station, in Minnesota I believe, and focused on the fact that this supernova was so close it could be viewed with simply a pair of binoculars (which is true). The bad astronomy comes between 2:25 and 2:37 in the video.


http://www.myfoxtwincities.com/dpp/news/scitech/space/supernova-visible-in-night-sky-sept-12-2011


Hopefully you watched it. Did you catch it? The reporter claims our Sun will come to the same fate and supernova 5 billion years from now! Obviously this reporter has never heard of the Chandrasekhar limit. Yes, our Sun will one day (there will no longer be days as we know them at this time because the Earth will have been swallowed by the Sun in red giant phase, not to mention the slowing of the Earth's rotation will result in longer days) be a white dwarf like the star that supernova'd, but in order for a white dwarf to supernova it must surpass the Chandrasekhar limit of 1.4 solar masses. The Sun will never reach that mass (obviously) and will be a quite stable white dwarf. But then, I think we all know Fox and science don't mix.

From Planck Length to the Universe

I think we take for granted, as physicists, the vastness of the field we are in.  Physicists study the the smallest things conceivable to the seemingly infinite reaches of the universe and everything in between. Here is a very cool thing I've discovered on Astronomy Picture of the Day that shows the scale of the stuff that makes up the universe (please go to the link!). From the plank length to the universe and many examples in between, it is awe inspiring to know how both small were are in terms of the universe and how huge we are in terms of the tiny bits of stuff of which we are made.

http://apod.nasa.gov/apod/ap120312.html

Here are some things which surprised me:


-The largest known star, Canis Majoris, has a diameter roughly that of the distance between the Sun and Jupiter!


-In the lifetime of the Earth, it has traveled (relative to the Sun) a distance about equal to the diameter of 5 Milky Way Galaxies!


-We can only observe an extremely small portion of the actual Universe


-You could place several neutron stars within the borders of Rhode Island


-A neutron star is not much larger than Mount Everest, but the highest mountain of a neutron star is about 10 cm!


-A transistor gate is too small to be seen, even with an optical microscope!


-The top quark is the smallest quark... by a lot!


-A high energy neutrino is largest than a regular neutrino


-There's something out in the Universe called Gomez's Hamburger :)

TIGRE Gamma-Ray Telescope

Just down the hall from where our Astro class meets for lecture, an interesting telescope sits in a lab. The TIGRE (Tracking and Imaging Gamma-Ray Experiment) Gamma-Ray Telescope. This is a balloon-borne telescope designed to map the universe in the 0.3-100 MeV range. Its design is quite ingenious and sets it apart from other Compton telescopes.


The detectors consist of essentially two parts, which are referred to as D1 and D2. D1 consists of 50 of more double sided silicon strip detectors (SSD). The events passing through these detectors are given X & Y coordinates and have an resolution of less than 1mm. D2 consists of 5 to 10 cadmium zinc telluride (CZT) strip detectors which surround D1 on five sides. This allows for detection of large angle scatter events and allows the telescope to also act as a gamma-ray polarimeter, both of which are new to Compton telescopes.


The Compton scattering event happens in D1 and the electron is tracked as it passes through the detector and the energy of the scattered electron is measured. The photon is then absorbed in D2. Timing and pulse height analysis are used to give the direction of the scattered photon. Because of this, the possible directions of the incident gamma-ray is greatly reduced from a ring to a small arc of the sky. Also, this telescope has background rejecting capabilities which leads to enhanced sensitivity and resolving power.


This telescope was last launched in April of 2010 in Australia. Both UC Berkeley and UCR were in Australia launching Gamma-Ray telescopes during this time. UCR went first and had a very successful launch. Later, it was Berkeley's turn. The following is a video of the disastrous launch of the UC Berkeley telescope:

Go UCR!

Here are some neat pictures of the telescope:

For more info on the TIGRE Gamma-Ray Telescope go to:

http://stratocat.com.ar/fichas-e/2010/ASP-20100416.htm