Wednesday, March 19, 2014

All mysteries solved??

I received an email from a relative, asking if the newly discovered “missing link” in astronomy now solves all the known mysteries. My original response was a defiant “No”—for how could observation of polarized light from gravitational waves at the time of the Big Bang, thereby proving inflation, be the answer to all of our mysteries? It definitely does not help answer the question of “how far away is epsilon Aurigae?” But it got me thinking about what impact this amazing finding will actually have on physics. Does it really solve all mysteries?

I first heard about the proof of inflation via a feed I get in my email. There is an excellent summation of what this really means on the Bad Astronomy blog from It is quite a complicated finding, but let’s see if I can write a brief summary of what it is and what the BICEP2 B-mode figure means.

The published figure shows polarization (the lines) “ripples” in the Cosmic Microwave Background (CMB), which were created during the inflationary period at the beginning of the universe. The lines show how the light/radiation/CMB is polarized. (Your polarized sunglasses block out light polarized in a certain orientation) The CMB is left-over radiation from the beginning of the universe—it permeates everywhere (that is shown in the blue and red). It is how the polarization “curls” that is the signature astronomers have been looking for. This is indicative of gravitational waves interacting with the CMB.

Now, why does this matter? The figure below gives a lot of information, but the point is that the inflation period happened quickly and allows for the gravitational waves to polarize the CMB. So, it is essentially proof of how the universe came to be—it helps answer how everything is. It provides a link toward the grand unification where the strong, weak, and electromagnetic interactions are all unified (see the 3rd figure, here). This is a wonderful statement from Phil Plait of Bad Astronomy:

“Inflation is based on principles of quantum mechanics, while gravitational waves are the purview of relativity. QM has brought us computers, solar power, atomic energy—a huge amount of modern tech. Relativity is critical in many aspects of our lives as well, including GPS and also nuclear power. In the past these two concepts haven’t played well together, but now we have a direct and profound connection between them. This result is new, and we have a long, long way to go to understand it better. There’s no way to know what will result from this. Yet. But whenever we open up new fields of science, all sorts of interesting things follow. Bet on it.”

So, let’s refine the opening statement: it solves many mysteries, just not all; and it will open the door to more.

Friday, March 7, 2014

The Future of Space Science

NASA's 2015 budget was unveiled earlier this week and, not surprisingly, the numbers weren't pretty. The proposed budget is 180 million less than for 2014, for a total of 17.5 billion. But only about 5 billion of this is NASA's science budget.  Large amounts of money are required for other NASA programs, specifically anything related to human spaceflight.  For example, development on the Orion capsule and rocket will cost 2.8 billion for the year, and commercial spacecraft development another 850 million.

However, in order to pay the bills associated with human spaceflight, NASA has resorted to gutting its other science programs.  For example, it plans to cut funding for SOFIA entirely. SOFIA is an infrared observatory that is mounted inside a Boeing 747.  The advantage of this telescope is that it can get above much of the interference/absorption from the atmosphere that ground-based telescopes suffer from while flying, but when it lands repairs or upgrades can be made, which is difficult (or usually impossible) on space telescopes.  This is also an international project, so NASA is letting their partner space agencies down in addition to the scientific community.  Of course I'm paraphrasing, but it sounds like NASA's official stance is that if the Germans want to use SOFIA, they can pay for it.

Jupiter's moon Europa
Jupiter's moon Europa
Of course there are science programs receiving funding.  James Webb Space Telescope got 645 million to keep it on track for a 2018 launch, and Planetary Science is getting 1.3 billion. However, most of that money goes toward Mars missions. While I acknowledge that NASA's Mars program has had numerous recent successes and yielded interesting results, there are many other interesting targets in the solar system that are being ignored as a result of this almost singular focus.  One example is a mission to Europa, considered by some to be the likeliest place in the solar system to find life other than earth.  This received only 15 million in funding - just enough for so-called "pre-formulation work" isn't even on NASA's long-term roadmap yet.

Plutonium pellet
Plutonium pellet
There's also the question of powering a Europa orbiter, or any future deep-space mission for that matter. Because you receive less light from the sun the farther you get away from it, probes sent deep into the solar system can't rely on solar panels to generate their power. Instead, they use a radioisotope thermoelectric generator (RTG), sometimes called a nuclear battery.  These contain plutonium-238 (not the isotope that goes into nuclear bombs).  The plutonium heats up to over 1200° C, and that heat can be converted into electricity.  The Cassini mission to Saturn and New Horizons to the Kuiper Belt both use RTGs.  Both Voyager probes can attribute their long lives to the reliability of power from an RTG.  So, what's the problem?  NASA only has 36 pounds of plutonium-238 left (the previously mentioned Europa orbiter would require 47), and it hasn't been produced anywhere since the 1980s.  Due to lawmakers dragging their feet on restarting production, it's likely that all the plutonium-238 on the planet will have been used by the end of the decade.

While NASA's Orion project may provide future PR for the space program, it is enormously expensive.  If only a fraction of the 2.8 billion it will get next year (or the 3.1 billion it got this year) was diverted into restarting plutonium production, NASA could save its planetary science program. The same goes for the approximately 2 billion it would cost for asteroid redirection mission planned for 2025, which in essence "creates" a destination for Orion. However, it seems that even given the reality that NASA's budget isn't getting bigger, politicians and administrators continue to choose big, flashy missions that give good photo ops rather than the ones that can give the most science for the money.  Now stepping down from my soapbox...

Thursday, March 6, 2014

Cosmos: The book and TV series

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I guess many of you saw the promo for the upcoming show called Cosmos: A Space-time Odyssey. If you haven't seen it yet then you should definitely watch it 
It is a 13 episodes television series featuring Neil deGrasse Tyson which will air in many television stations from March 9th. It is a follow up of 1980 Cosmos: A Personal Voyage by Carl Sagan . You can watch all the episodes from the series in youtube. There is also a book titled Cosmos by Carl Sagan. This book and the television series have many crossovers as well as different content.
I highly recommend every one to watch this documentary as it is informative and easy to understand. If you prefer to read, then Cosmos will be a good read (in case you haven't read it yet). The book is written in plain English and you don't need to have science background to understand it. It is one my favourite books of all time. What I liked the most about this book was information on the history of science, astronomy in particular. He discusses about how different civilizations approached scientific endeavours. I was left in awe when I read about many historical persons who achieved so much at time when there was not much to work with. In addition to historical events there are many other interesting stuffs in this book. It tries to answer the basic questions about our cosmos which most of us have wonder at some point in our lives.
Do you have any recommendation for other good books?

Wednesday, March 5, 2014

Asteroids Galore!

Another asteroid just made a close approach! Asteroid 2014 DX110 was closest to the Earth at 4pm EST.

How close?   According to the officials at NASA's Jet Propulsion Laboratory in California, the asteroids closest approach was about 217,000 miles, which is about 350,000 km. Remember, the average distance from the Earth to the moon is 239,000 miles. That means this asteroid just passed between the Earth and the moon!

Now, for us here in Denver, or even those on the East Coast, the sun is still up. You couldn't see anything. Even for those people on the other side of the globe, you still couldn't see anything without a large telescope. This asteroid only has a diameter of 100 meters and thus is very, very faint. Even with some larger telescopes, this asteroid was moving so quickly, it was still hard to track.

The image on the right shows the asteroid that just made its close approach in relation to the background stars. 2014 DX110 is highlighted in a box and blown up so you can see what the object looks like. Mostly, it just looks like just another background star, except for the streak, which was caused because this asteroid is moving so quickly.

The image to the left shows the path the asteroid took as it made its close approach. The path that is depicted is how far the asteroid traveled in only 2 hours! Because this asteroid moves so quickly, it makes it very difficult to track. 

Why might you not have heard about this object? Most likely because it was only discovered last Friday, announced by the Minor Planet Center on Sunday, it is faint, and it won’t be impacting Earth. Although, Slooh hosted a live event detailing this asteroid as it made its close approach. You can watch it here and catch up on all the details.

During the show, the host mentioned that there is going to be another asteroid the will pass extremely close to us within the next couple of days. This object is 2014 CU13, an asteroid of about 20-46 feet in diameter. This asteroid will pass within 37,000 miles of Earth!! Slooh will be hosting another live show on Sunday to track this asteroid.

Sunday, March 2, 2014

Science kids

I was in a thrift store the other day looking through the vast number of available children’s books for my toddler son. Out of all of those books, I found a book with a black and blue cover with semi-purple lettering; there were white spots across the front and a misty, blue-purplish region in the upper left. Sure enough, it was the same book I had as a child: A Book About Planets and Stars.
I could remember spending hours staring through the pages and soaking in the variety of features our solar system holds in its planets. I don’t know how much influence that had on me choosing to become an astrophysicist, but I know I loved it then.

And just the other day, my 2 ½ year-old asked me to read him that book before bed. We went through the inner solar system (Mercury, Venus, Earth, Mars) and discussed (yes, discussed!) the differences between these planets. Okay, we just discussed the difference in color, but even then we talked about why. And I’m pretty sure he knows each of the names of the planets now.

Anyway, the point of this post is not to brag about my son, but to point out the importance of helping kids get excited about science/astronomy/physics. From television shows—for instance, Zoom, Bill Nye the Science Guy, and Sid the Science Kid—to youth programs—such as Odyssey of the Mind, FIRST LEGO League, FIRST, YAE— there are a lot of ways for children to participate and compete/learn.

The figure above shows data from APS, documenting the number of physics bachelor’s over the last 45 years, verse the number of bachelor’s in STEM fields (including the medical sciences). It is interesting to note the peaks of the physics numbers: the first peak follows the landing on the moon (1969); the second precedes the successful Pathfinder mission to Mars in 1997 (the first since 1976). I don’t know if the scientific programming as stated previously had anything to do with the increase since 2000, but it is great to see this increase occurring.

The important thing is to help spread the joy of science and discovery to people of all ages, especially those that will influence the path of science for the next generation. Any other thoughts of ideas?

And here are sum fun images regarding Moon and Mars missions from wikipedia:

Friday, February 28, 2014

Space Technology

NASA phone comparison
You may have heard quips about how primitive the electronics used in space technology are compared to what you can buy as a consumer. This can be a puzzling fact given that space exploration is a very technical (and expensive) enterprise.  If we're going to spend hundreds of millions or billions of dollars to send a spacecraft out into the solar system (most of which just goes to getting to your destination), why give it old brains?

In fact, the example of the computers in the lunar landers isn't a very good one to illustrate the point I am trying to make.  While the computing power available is very small compared to devices today, it was actually quite advanced for the time.  So why would I mention an example that doesn't fit with the norm?  There are a couple reasons why technology in the early days of space exploration was more up-to-date than it is today.  The first is easy:  We were engaged in the "space race" with the Soviet Union.  NASA had an enormous budget compared to today, and was given the directive to take whatever steps (and often, risks) were necessary to win the race.

rope core memory
Core rope memory
The second reason takes a bit more explanation. The picture to the left is of a massive 128 byte (wow!) memory module from the Apollo Guidance Computer.  This is what is known as core rope memory, which means that a person sitting in a factory literally wove the wire into a pattern encoding the data. does that explain why Apollo-era technology could be sent into space easier than today's electronics?  If a human being put the memory modules together, that means the wires must have been at least a minimum workable size.  But consider current generation CPUs.  The size of transistor gates is 22nm.  For comparison, a human hair is about 50,000nm across and a silicon atom (which microchips are made of) is 0.11nm.

solar flare
A Solar Flare
Both core rope memory and new computer components work fine on Earth, so why not in space?  The difference is that outer space is constantly flooded with radiation from the solar wind and cosmic rays, but (luckily for us) Earth's magnetic field protects us from most of this.  When enough highly energetic particles are passing through your spacecraft, one is bound to hit something important and transfer that energy into whatever it hits.  In old electronics that wasn't a big deal - the components were big enough that the energy could spread out and cause few problems.

Newer components are a different story.  As you may have noticed above, the current generation of computer parts have die features on the scale of a few atoms.  This means that it doesn't take very much energy to flip a digital bit from 1 to 0 or back. That's good when you need to power a CPU with over a billion transistors but very bad when you're being bombarded by high-energy radiation.  Then again, I'm not sure that's ever a good situation to find yourself in...  When a bit flips in a memory chip (usually causing a crash or data corruption), that's called a soft error.

Clearly, electronics on spacecraft must be different than personal computers to function in their environment. Any component that leaves Earth's protective magnetic bubble must be radiation hardened.  There are many techniques for accomplishing this, but they fall into 2 general categories. Curiosity imageFirst, the components are often manufactured using different materials and surrounded by radiation shielding to prevent errors.  Second, there can be error correcting codes for memory and redundant calculations to check for errors that have already occurred.  All of this adds complexity to the design, which then must undergo multiple rounds of testing before it has a chance of seeing spaceflight.  This testing process, which is essential to ensuring spacecraft systems continue functioning after we hit "launch," is why these systems are less powerful than what you can buy at any electronics store.  So rather than making fun of NASA's newest Mars rover, Curiosity, for having a camera with less resolution than your cell phone (it's 2 MP), just enjoy the images it takes and remember that it survives being bombarded by radiation every day.

Thursday, February 27, 2014

Telescopes a window to the universe

A telescope is an instrument made up of lens or mirror to observe the far away objects. A telescope magnifies and brings object much closer. Thus making the study of far away object much easier. The first telescope was invented in Netherlands in 17th century. Soon after that Galileo made similar telescope and used it to study the sky.
Observation of moon by Galileo and the picture he made from the observation.
Above link gives us brief history of the telescopes.
The above image illustrates a very simplistic view of how a telescope work. Initially telescopes were made using lenses, later the use of mirror was introduced. There are various types of telescopes in use now.
It can be divided based on what range of electromagnetic waves we are looking at. The light we see is also a collection of a range of electromagnetic (EM) wave.  EM waves can be divided into various categories based on their wavelength. There is very limited range of wavelengths that a human eye can perceive.
Electromagnetic wave spectrum
Brief classification of telescopes on the basis of wavelength
a) Optical telescope
b) Radio telescope
c) X-ray telescope
d) Gamma ray telescope
e) Infrared telescope etc.

These different types of telescopes are used for different proposes. For example
the image here shows the galactic centre but
they are observed by different types of telescopes (i.e. in different wavelengths).
So depending on what they are trying to understand, scientists use different types of telescopes. Even though the older telescopes were ground based (i.e. they were used from the earth for observations) there are many telescopes now which are space based. Some of them are Hubble, Sptizer, Chandra etc. There are lot of beautiful images taken by these telescopes which you can find very easily in the internet.

Also the sizes and weight of telescopes varies a lot. There are telescopes weighing few pounds to thousands of pounds.
I encourage everyone to look through the telescope whenever you can. Most schools with observatories have open house. You can see many wonderful celestial objects through these telescopes if you go to an open house. Here at University of Denver, there is one open house at old Chamberlin observatory every month for the public. If you are in Denver area you should definitely make use of it. Click here to get more informations regarding the open house.