The Origin of the Big Bang... from the South Pole

By Yuki Takahashi, NASA Student Ambassador, UC Berkeley

I have been working with a team on a new telescope that we set up at the South Pole to learn about how the Big Bang started. We know that our universe had what we call the "Big Bang", meaning that it seems to have started from a tiny volume of concentrated energy, which then expanded as the universe itself stretched to the huge volume we see today. What may sound amazing is that we can still "see" the radiation from that beginning when the universe was much more concentrated and hotter. It's called the cosmic microwave background radiation. Astrophysicists in the 1960s detected this radiation (Nobel Prize) and in the 1980s found fluctuations of it across the sky (Nobel Prize 2006). We think these fluctuations came from quantum fluctuations that got stretched during the first tiny fraction of a second of the Big Bang when the universe seems have inflated extraordinarily fast, seeding density fluctuations that eventually became galaxy clusters of today. We also think that this initial "Inflation" produced ripples in space-time called the "gravitational waves", which has never been detected yet. If we can learn about these gravitational waves, we can find clues about the ultimate question of how the Big Bang started.

To look for a sign of these gravitational waves in the radiation from the Big Bang, our team of ~10 astrophysicists (Caltech/JPL, UC Berkeley, UCSD) developed a telescope and set it up at the South Pole last year. Because the microwave radiation gets blocked by water molecules (as you may know with microwave ovens), we chose the site with the least amount of water vapor in the atmosphere. The South Pole is at ~2800 meter altitude, above much of the water vapor, and its cold air doesn't hold much moisture. It's one of the best sites on Earth for studying the cosmic microwave background, although going to outer space is even better!

Ours is actually a precursor to a space-based telescope (Inflation Probe). Just like in any space mission, we kept the telescope compact to save cost while meeting the required performance. Because the site is so remote and not easily accessible, we designed and developed the telescope's motion control system and various electronics to be very reliable.


After shipping out most of our telescope parts in October 2005, I flew to the South Pole in November with 2 other members of our team. We began setting up our lab and our telescope in a new empty building about 1 km walk from the main station (which is right by the geographic pole). Even in -45°C weather with winds, walking in a gear almost as bulky as the spacesuit makes you warm. The desolateness made me wonder if it was anything like being on the Moon... More of our team arrived later and some went back. By the end of my 2-month deployment, we were able to get the telescope working. From March to October 2006, we used our telescope to map a small patch of the sky, integrating down in search of what is expected to be a very tiny gravitational-wave signal.

After a successful year of observations, my teammates and I went to the South Pole again to replace several of the telescope's ~100 detectors and calibrate them. We completed our planned 3 years of observations and have replaced the telescope with a next generation one. The gravitational-wave signal from Inflation is likely to be at least an order of magnitude smaller than even what the current WMAP satellite has been able to sense. By concentrating on a small patch of the sky with our array of sensitive detectors, we may have a chance. In any case, our experiment will be able to narrow down the possible explanations for how the Big Bang began.

Through our exploration of the beginning of the universe, it has been a privilege to be able to explore one end of the Earth. Some day, I would like to try living at the South Pole through its dark cold winter. And eventually, I would also like to go to the South Pole of the Moon . As we continue to explore space, there is probably a lot more to learn from experiences in Antarctica.