Speaking of Hubble...

Archive: June 2012

When Galaxies Collide; Stars Don’t

June 28, 2012 by Frank Summers
Arp 148 is a unique snapshot of an ongoing collision.

Arp 148 is a unique snapshot of an ongoing collision.

In a recent blog post, I discussed the collision between our Milky Way galaxy and the Andromeda galaxy. In about four billion years, the two vast, spiral shapes will combine and transform into a single elliptical galaxy via a powerful gravitational smash-up.

News of the awesome collision prompted many to ask about what happens to the stars within the galaxies. In particular, what might happen to our Sun and the planets around it.

The good news is that when galaxies collide, the stars inside them won’t crash together.

To understand why, one has to recognize just how far apart the stars are. It’s easiest to explain with a scale model.

Suppose the Sun were the size of a baseball. I live in Baltimore, so let’s imagine this baseball is located at home plate in Oriole Stadium.

One of the stars nearest our Sun is Alpha Centauri. Let’s also shrink that star down to a baseball for our scale model. The question is: where would the Alpha Cen baseball be located?

It would not be in the infield, or the outfield, or anywhere in the ballpark. It would not be in the city of Baltimore or even in the state of Maryland. For a correct scale model, the Alpha Cen baseball would be about 1,300 miles and many states away — in Houston, Texas.

One baseball in Camden Yards and one baseball in the Astrodome — that’s the relative size and separation of the stars in our part of the galaxy. You can see that there is a lot of space between Baltimore and Houston for other baseballs to pass through.

Hence when galaxies collide, the stars stream past each other at vast separations. The orbit of our Sun within the combined galaxy may change greatly, but the orbits of the planets around the Sun will not be affected.

One can rest easy knowing that our solar system will survive the great collision between the Milky Way and Andromeda. However, that doesn’t mean that the billion-year future of Earth is all rosy. There are other factors that will greatly alter our planet. I’ll discuss those in my next posting.

Sharing Astronomy With All

June 14, 2012 by Mangala Sharma

Saturn's ringsThere’s so much about our cosmos that engages our sense of wonder and awe. Through astronomy, humans hunt for answers to some of the most fundamental questions that tease our curiosity and intelligence.

Practically everyone around the world participates, to varying degrees, in astronomy. We may be occasional observers, led by our natural fascination with the sky, aware of how the Moon waxes and wanes, or we may gasp over the momentary splendor of a “shooting star.” We may follow astronomy news daily or pore over gorgeous astronomical images on websites such as HubbleSite. Some of us contribute our computer’s idle CPU cycles to cool projects like SETI@Home, searching for extraterrestrial intelligent life by analyzing cosmic radio signals. Hundreds of thousands of people are amateur astronomers or citizen scientists, observing the skies themselves or delving into the thicket of archival astronomy data. And a handful of us are professional astronomers, a niche market of only about 15,000 worldwide.

I love the fact that, at any point in time, somewhere on (or just above!) the Earth, humans are accessing astronomical experiences and discoveries. Access to such data or discoveries doesn’t happen by magic, though. It takes the creative and dedicated efforts of a large community of professionals or volunteers. Scientists and engineers working on astronomical archives and data centers such as the Space Telescope Science Institute’s (STScI) Mikulski Archive for Space Telescopes (MAST) make their collections available to not only professional astronomers, but also citizen scientists and anyone with an Internet connection anywhere in the world. There are thousands of college professors, teachers and education/outreach professionals preparing future generations of scientists and a science-literate public all over the globe. Amateur astronomers are wonderful ambassadors, connecting people to the wide cosmos through a telescope’s eyepiece.

Personally, I have benefited from every such effort, and strive to return the favor. Among my favorite memories from my days as a student in India is participating in, and then helping run, a telescope-making workshop for high school students: in barely 10 days, we made concave mirrors by grinding and polishing 6- or 8-inch glass blanks by hand, and used plastic tubes and store-bought eyepieces to rig decent reflecting telescopes. You can imagine our pleasure at seeing Saturn and distant nebulae through a ‘scope we’d built ourselves – everything looked gorgeous, even in poor seeing conditions or through patchy clouds!

For some years now, with other professional and amateur astronomers, I’ve taken small solar telescopes (with safe solar filters) to neighborhood farmer’s markets. It’s delightful to hear people exclaim as they see sunspots or solar flares, and experience the complexity and beauty of our own star.

Currently, I work at STScI’s Office of Public Outreach, being paid to do what I love – sharing astronomy. The tradition of sharing astronomy with all easily goes back to the Renaissance. Galileo, who first turned a spyglass skyward, took his handmade telescopes to the streets and gave the common man a chance to discover the craters of the Moon and the phases of Venus.  In 2009, we celebrated the 400th anniversary of Galileo’s pioneering work as the “International Year of Astronomy” (IYA). The UN-declared IYA encouraged people across the globe to get close and personal with astronomy, discover the universe for themselves, and gain a deeper appreciation of astronomy’s place in human culture. And millions of people all over the world did. Perhaps some inspired students will go on to become scientists themselves.

Which brings us to the question: why do we work to make astronomy available to all? For one thing, it’s the taxpayers that provide the majority of funding for professional astronomy. It makes sense to share with them the scientific returns on their investment, and garner their continued support for science. Science is more and more relevant to everyday life, and it’s in our best interests to ensure that people bring well-informed perspectives to policy decisions that affect scientific pursuits. Just as importantly, it’s a culture and viewpoint thing. “One sky connects us all!” goes the tag line for the American Astronomical Society. Can’t argue with that.

Dragon’s Lair

June 5, 2012 by Alberto Conti
Maneuvering Dragon to the docking port of the International Space Station. CREDIT: Andre Kuipers/ESA/NASA

Maneuvering Dragon to the docking port of the International Space Station. CREDIT: Andre Kuipers/ESA/NASA

On the tail of my last post about Planetary Resources’ goal of mining asteroids, last week I was reminded on three separate occasions of the excitement I often feel when thinking (and dreaming) of our place in the universe. It’s a remarkable time.

First, on May 20 (May 21 in in the Eastern Hemisphere), a spectacular annular solar eclipse took place. Such an eclipse occurs when the Moon passes between Earth and the Sun, partially obscuring the image of the Sun for lucky observers here on Earth. The key word here is “partially.” In these types of eclipses, the Moon is unable to completely cover the surface of the Sun, leaving an annulus known as the Ring of Fire. Fortunately, even if I was not one of the lucky ones to view the event in person (the eclipse was not visible from the East Coast of the United States), an abundance of live feeds on the Internet allowed me to truly feel part of the action.

Then, on May 25, the board of the Square Kilometer Array (SKA) Organization convened in Amsterdam to announce their final decision on the site that will host the SKA radio telescope. This decision was important for astronomy in that SKA will be the world’s largest and most sensitive radio telescope ever built. The decision was an anticlimactic tie, in that SKA antennas will be hosted both in South Africa and Australia, but this was somehow expected. SKA is big science with the potential of big discoveries, and many wanted to be part of it.

I will come back to SKA in an upcoming post, given that in this case big science truly means big data as well.

Finally, a Dragon ran from Earth but was captured by the International Space Station (ISS). Just when many of us looked with apprehension at a future without reusable vehicles like the Space Shuttle, and thought that exploration had effectively been put on hold, NASA sanctioned a commercial company to deliver “groceries and supplies” to the ISS, thereby opening the door for a viable commercialization of space. The successful mission of the unmanned cargo capsule, named Dragon, could potentially be a game changer, particularly if companies like SpaceX will initially take the role that FedEx on Earth has assumed for our personal packages. However, in light of Planetary Resources’ announcement, I believe many companies are now on a trajectory that will put them at the forefront of space exploration: delivering packages is just a required stepping-stone. SpaceX needs to learn how to dock before it can plan on orbiting another planetary body.

Most of the success of companies like SpaceX is due to the remarkable ingenuity and entrepreneurship of people who simply never stopped dreaming about space. A few individuals, after having made a fortune in business, are now turning to their “hobby.” Luckily for all of us, their hobby is the exploration of space. This is indeed the case for Elon Musk, CEO and Chief Designer of SpaceX. He co-designed one of the first viable electric cars of the modern era, the Tesla Roadster, he co-founded what is now the world’s largest Internet payment system, PayPal, and he built SpaceX, the first commercial space company able to send its own capsule to the International Space Station.

SpaceX has effectively opened a new era for private spaceflight after the end of the 30-year U.S. shuttle program. I think this maiden flight and docking to the ISS will someday be recognized as a historic event, even if only for the potential to inspire others to reach further in our planetary neighborhood.

Elon Musk is only 40 years old, and if the past is any indication about his capabilities of turning ideas into products (SpaceX was founded just 10 years ago), I expect to see a big push in the coming years for a much bigger mission: Mars, within his lifetime.

It’s starting to feel like the early 60s all over again: a time where anything in space seemed possible!