Q & A – An Astronomer’s Window

minisciencelogo-300pxAt the conclusion of each Mini-Science lecture, audience members submit their questions to the evening’s presenter, who answers as many as possible on the spot. Three of the unanswered questions are sent to the presenter for posting here. In addition, a quiz is held each week based on material from the lecture. Here are questions and the quiz from Prof. Matt Dobbs’ lecture ‘An Astronomer’s Window on the Birth of the Universe’ (April 8, 2009).

Q: Can we infer where we are in the universe by knowing how far back we can see in different directions?

A: No. We can see the same distance in any direction: the age of the universe times the speed of light. The universe appears essentially isotropic in all directions. This DOESN’T mean we are at the center of the universe or even that the concept of a center or edge to the universe is valid.

Q: What are some of the challenges of operating a telescope at the South Pole?

A: There are many challenges! The extreme cold poses challenges for both the equipment and people. When servicing or constructing the telescope, much of the work must be done outdoors, with temperatures frequently well below -50C. Working with intricate components with big mittens on can be challenging! The telescope had to be designed to withstand large thermal gradients. Finally, the remoteness of the site means a great deal of preparation is necessary. For 8 months of the year, no one is able to travel to or from the site – our winter-overs (the people who spend the antarctic winter operating the telescope) need to have spare components to fix any conceivable problem and the skill and creativity to handle the inconceivable problems that inevitably arise.

Q: Can you determine where the beginning and the end of the universe are?

A: Yes and no. Assuming the Big Bang model, then we are today at the location of both the beginning… and so is every other point in the universe. In this model, the universe grew from an expansion of space-time. Our little corner of the universe is part of that original singularity. If the universe comes to an end (for example, in a big crunch), space-time points may collapse together once again. In this manner, every location in the universe shares the title of being the location of both the beginning and the end.

Quiz

Q: Why is the South Pole Telescope located at the geographic south pole?

A: This telescope observes mm-waves, which are absorbed and emitted by the atmosphere and water vapor. The south pole is 3000m high and one of the dryest places on earth. Being HIGH and DRY means there is much less atmosphere to look through.

Q: What is the “smoking gun” evidence cosmologists are looking for that would support inflationary theories?

A: Gravity waves emitted from the time of inflation would imprint their signature on the polarization of the microwave background radiation.

Q: What is enabling the precision cosmology measurements scientists are making today?

A: In most cases, technological advances are allowing us to look for signatures that have been predicted for a long time- we’re only now learning how to build instruments sensitive enough to measure them. For example, the distortion Galaxy Clusters imprint on the Cosmic Microwave Background radiation was predicted in the early 1970s and we’re only now discovering Galaxy Clusters this way for the first time.

If you have any related comments or questions, please feel free to post them. We cannot promise a reply to every question but will answer what we can.

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