Bench Press

I have always been impressed with the work of astronomers. Unlike biologists and chemists who can, for a wide array of topics, actually touch and feel what they are studying, astronomers have to make conclusions with only careful observations conducted with powerful telescopes and computers informed by understanding the laws of physics (quantum and relativity included) and backed up by complex computational models.

One phenomena which astronomers can use to better explore deep space is an effect predicted by Einstein’s theory of general relativity called gravitational lensing. General relativity predicts that the path of light can be bent by gravitational fields; the most dramatic example of this would be a black hole, where gravity is so strong that light “falls” back into it. The same effect, on a less dramatic scale, could result in the path of light being bent on its way to Earth by the gravity of another object. The term “gravitational lens” refers to the fact that this bending is similar to the bending of light by a telescope lens.

Now, for the layperson, the fact that light can bend is probably just a cool effect which has no practical importance. But, to a well-trained astronomer, the knowledge of how gravity works lets them use the phenomena of gravitational lensing to understand both the objects that are emitting light (because the lensing effect allows us to see objects which are so far away that they are blocked by another object) and the “lens” itself (understanding the mass, structure, and position of what is bending the light).

Take a look at the pictures (HT: Wikipedia) below of Einstein rings. These occur when the line of sight to a bright, faraway object is being blocked by another object. However, because of the gravitational lens effect, the light from that faraway object can bend around the closer object, resulting in a ring which gives scientists a chance to study not only the faraway object but also understand the structure of the intervening space.

There are countless other examples of the application of gravitational lensing in the study of astronomy, but one of the most clever that I heard about recently was the study of dark matter. The theory in a nutshell: the universe is believed to be mostly dark matter – matter which does not reflect or emit any light whatsoever. Because it doesn’t seem to emit or reflect electromagnetic radiation, there has been no direct observational way to study it. However, dark matter does have mass. This means it has gravity and can thus bend light as a gravitational lens!

Researchers were able to took astronomical survey data from around the world and, using sophisticated computer algorithms and programs, compile a picture of gravitational lensing due to dark matter. From that, they were then able to digitally put together a picture of the structure of the dark matter in (at least part of) the universe and get a sense for how it’s evolved over time (the further from Earth you look, the further back in time):

And with this they made a striking conclusion – we all have dark matter to thank for the existence of the stars and the galaxies:

Our results are consistent with predictions of gravitationally induced structure formation, in which the initial, smooth distribution of dark matter collapses into filaments then into clusters, forming a gravitational scaffold into which gas can accumulate, and stars can be built.

Awesome.

(Image credit) (Image credit)

Despite all the cool and meaningful innovations we’ve discussed on this blog, few come as close in terms of impact on a scientific field as the Hubble Space Telescope. And this weekend, you can help celebrate it’s birthday!

Officially launched on April 24, 1990 (can you believe that was 20 years ago!?), it has provided one of humanity’s best looks into deep space and has, among other things:

• Helped refine the field’s understanding of Hubble’s Law and the Hubble Constant
• Showed that the expansion of the universe was not decelerating, but accelerating, suggesting the existence of dark energy
• Helped to establish the existence of massive black holes at the center of galaxies and their relationships
• Provided sharp images of the impact of comet Shoemaker-Levy 9 into Jupiter
• Collect data on extrasolar planets and protoplanetary discs
• Furthered the study of Wolf-Rayet Stars, suspected to be the precursors of Gamma-ray bursts, the most powerful energy bursts known in the universe
• The mindblowing look 13 billion years into the past known as the Hubble Deep Field

And, potentially, most important of all: the gorgeous pictures of deep space (from Space Telescope Science Institute’s HubbleSite website).

Happy 20th birthday, Hubble!

(Image credits – Hubble Site via Space Telescope Science Institute)

Previously we’ve covered the extensive tracking and modeling of near-earth objects NASA undertakes as well as efforts to pass along data to the public via the internet. In Ben’s post about modeling near-earth objects he wrote about a specific asteroid designated 99942 Apophis. Discovered in 2004, it has been closely scrutinized by astronomers worldwide as it’s size and potential for collision with Earth have sparked interest.

Meet Apophis. Discovered in 2004, it will likely set a record for harmless near earth pass in 2029.

Earlier data pointed to the asteroid potentially passing through a troublesome gravitational keyhole which increased the threat to Earth in 2036, however new data from previously unreleased images from a University of Hawaii telescope near the summit of Mauna Kea have allowed NASA scientists to improve their models. New models show a reduced risk of collision in 2036 from 1 in 45,000 to 1 in 250,000.

From the NASA press release:

“The refined orbital determination further reinforces that Apophis is an asteroid we can look to as an opportunity for exciting science and not something that should be feared,” said Don Yeomans, manager of the Near-Earth Object Program Office at JPL.

Modeling asteroids and allowing humanity a chance to risk assess is only one example of the power of computer modeling. However, this example also illustrates one important caveat about modeling. One’s model is only as good as the data utilized in generating and analyzing it. Let’s hope that future data on Apophis continues to produce good news.

(Image Credit)

We’ve previously covered the computer modeling solutions being used to model and track the paths of near-earth asteroids (especially those which might treat Earth like a dartboard), but for those of you not content to just sit at home while NASA scientists do all the tracking, the asteroid trackers at NASA’s Jet Propulsion Laboratory have made it now easier to follow what’s going on in the world of near-earth asteroids from the comfort of your own home.

The first little gadget they’ve developed is a computer widget (pictured on the left) which is compatible with the Mac OS and Yahoo widget engines.

What it will show is a list of the next five near-earth asteroid approaches (within ~20x the distance of the moon) and an estimate of their size (including a pictogram depiction of what that size means) as well as their distance. The widget will also make it easy to find more information about the particular asteroids it is identifying (an example is linked here) which will show off a dynamic Java applet map of the asteroid’s orbit through the inner solar system (which you can manipulate so you can see how the orbit looks in 3D) as well as a wide range of data on the asteroid such as the eccentricity of an asteroid’s orbit (in layman’s terms, how oval-like versus how circular), the orbital period (the time it takes for an asteroid to complete one rotation around the sun).

The second thing the brains at NASA’s JPL have put together for researchers and amateur astronomers is a Twitter account (@AsteroidWatch), which accompanies NASA JPL’s main Asteroid Watch site. The feed went live on July 29, 2009 and, although not written in the cutesy voice of the MarsPhoenix twitter account (which followed the exploits of the Phoenix Mars probe NASA launched a while back), the AsteroidWatch feed so far has reported on near-earth asteroids and new reports and articles issued by NASA’s official asteroid tracking team.

You can follow the BenchPress team on Twitter! You can follow us at Anthony (@AnthonyPhan), Ben (@BenjaminTseng), Eric (@EricSuh), and Kevin (@Kevin_Tseng).

We previously discussed using the powerful Wolfram|Alpha tool to look up medical/biological information, but did you know it also works for astronomical information also?

The Wolfram|Alpha blog lists a couple of great tricks, including:

• the ability to identify the stars in the sky based on your location
• looking up information about a specific star’s distance, brightness, spectral class (astronomy nerds out there know the “Oh Be A Fine Girl Kiss Me!” classification system), mass, and even surface temperature!
• looking up information about the next lunar and solar eclipses, sunrises, and sunsets
• looking up general information about the planets in the solar system

What I find most impressive, however, is Wolfram|Alpha’s ability to generate graphical depictions of the information you’re looking for, whether it be understanding what you’ll see when you look up in the sky:

Visualizing the path of the sun for a particular day:

Or getting a sense of the 3-body-configuration of the sun, moon, and earth:

Chalk this up as yet another cool thing you can do with Wolfram|Alpha!

(Image credit: Wolfram|Alpha and Wolfram|Alpha blog)

On Bench Press, we usually discuss technologies to empower scientists to do research or to better communicate with each other and with the public. But, technologies can also help the “casual” fan appreciate science as well. Case in point: Google recently announced a new application available for Android phones called Google Sky Map. The concept is quite ingenious. If ancient navigators used starcharts and compasses to determine their location, why can’t a phone that knows its location (via built-in GPS) and its direction (via magnetometer and accelerometer) be used to figure out what stars are up above?

Or in other words, Google took this physical setup (very cute setup from Google for how Google Sky Map works) of what is basically a sextant, compass, and calendar:

And replaced it with a smartphone:

I haven’t had a chance to play with it (as I don’t own a G1), but the application looks very nicely packaged. You can use it to figure out what stars are right above you. But, the coolest feature is the ability to use the application to point you in the direction of something you’re interested in seeing (e.g. the planet Saturn).

More details are in the video below. You can get Sky Map for Android through the Android Market. For anyone who’s tried it, let us know what you think in the comments!

(Image credit – Google)

The most amazing thing about social media services like Twitter and Friendfeed is how rapidly you can find interesting articles and links. One of my good friends on Twitter, Charles Ju, recently pointed me to a picture which he only described as “this picture blows my mind”.

And sure enough, it completely blew my mind. I re-shared it on my own FriendFeed (garnering a couple of comments/responses from my own Twitter followers and Friendfeed friends) If you didn’t understand the scale of the universe before, this will put it all into perspective:

A big wow for:

1. How powerful social media services like Twitter and Friendfeed are for disseminating cool information/factoids/images
2. How vast the universe is
3. The capability of the Hubble Space Telescope to amass information about our universe

PS: If you’d like to follow the Bench Press authors on Friendfeed/Twitter you can follow me at http://www.friendfeed.com/benjamintseng, Kevin at http://friendfeed.com/ktseng, and Anthony at http://friendfeed.com/atphan.