The professor is taking a much-needed day off from astronomy today. But I would like to take time to recognize those who have given their lives in service to the United States. While the reasons behind a war can always be debated, the men and women who serve in the Armed Forces have my deepest respect.
Saturday, May 27, 2006
I got to thinking that, if I were to go 20 miles straight up instead of to the west, I would die from lack of oxygen. I'd be in the middle of the stratosphere, and also in the midst of the ozone layer. The temperature would only be about -20 Centigrade (-4 Fahrenheit). The air pressure is only 0.01 atmospheres (it is 1 atmosphere at the Earth's surface) -- I would be above 99% of the atmosphere!
This gave me some appreciation for how thin Earth's atmosphere really is.
Thursday, May 25, 2006
Tuesday, May 23, 2006
(If you did not read my last entry, read it first, please.)
So, I have given an example of the level of controversy surrounding the Big Bang to try and illustrate varying degrees of scientific controversy. Out of tens of thousands of professional astronomers, fewer than 100 would claim that the Big Bang Theory is controversial. Many more would question the idea of inflation, and most would say that the details of the theory of inflation are controversial. And almost every astronomer would say that what came before Inflation is controversial.
Now let's look closer to home. Recently, global warming has been in the news again. Al Gore's new movie claims it is true, while large petroleum corporations strongly argue that global warming is controversial. So, from a scientific standpoint, is global warming controversial?
I recently learned of a study published in the journal Science. This is a highly-respected journal read by most scientists in the United States. In December 2004, scientists writing in the journal did a search for all articles published between 1993 and 2003 in peer-reviewed journals containing the words "climate change" in the abstract or keywords. What does this mean? It means that they searched for articles claiming to be about climate change, and that these articles had all been reviewed by another professional scientists with expertise in the field.
The search found 928 articles, or an average of seven per month. Of those, not a single article disagreed with the view that global warming is occuring and is due to greenhouse gases being released by human activity. Now, to be fair, 25% of these articles are about past climate change (like Ice Ages) or about methods of detecting climate change, and take no stand (for or against) current climate change. But still, this leaves nearly 700 articles by professional scientists stating that humans are causing global warmingm and not a single article suggesting otherwise. Think about it -- this is 100% agreement! How often does this happen?
Some of you might claim that scientists are suppressing opposing viewpoints. But let's go back to astronomy and the Big Bang. Remember that all but a few astronomers strongly believe in the Big Bang. Despite this, we still allow articles by those few astronomers to be published in our professional journals. It would be easy for us to suppress these viewpoints, but we do not. The same is true in other areas of science. Dissent, controversy, and the resolution of these differences is what propels science forward.
When I heard this statistic from Science Magazine, I was astounded. I've never heard of 100% agreement on any issue, though some (like the Big Bang Theory and the Theory of Evolution) come close. Not even 100% of astronomers believe in Albert Einstein's General Theory of Relativity!
So, it is time to face up to the truth. According to people who have spent their lives understanding the Earth's climate and how it changes, the Earth is warming up, and it is due to humans. It is no longer time to ask if global warming is occuring, it is time to ask what we are going to do about it!
Monday, May 22, 2006
Seems like you can barely pick up a newspaper or read news on the internet without someone claiming that established science is "controversial." More on that tomorrow. But first, we need to understand the levels of disagreement in science. To do that, let's talk about the Big Bang.
The Big Bang is the theory that the Universe originated from an incredibly hot, dense, and energetic "explosion" about 13 billion years ago. All the matter in the Universe today was compressed into a region much smaller than the size of an atom way back then. Since then, the Universe has been expanding and cooling, with the matter combining in different ways to make the galaxies, stars, planets, and so on that we see today.
Although the Big Bang is referred to as a "theory," it is as close to fact as one can get. There are well over 10,000 professional astronomers in the world, and all but a few (maybe 10-20? I can name four) believe that the Big Bang Theory is an accurate description of the Universe from about 10^-32 seconds (one hundred-millionth of one trillionth of one trillionth of a second!) to the present. So is the Big Bang Theory controversial? No! It's barely even debated.
Just before the Big Bang, many astronomers believe was a period of "inflation," when the Universe expanded much, much faster than the speed of light. This period would have only lasted 10^-32 seconds, and the Universe went from much smaller than an atomic nucleus to the size of a grapefruit. It doesn't sound like much, but the Universe grew in size by one hundred QUINDECILLION times (a one with fifty zeroes after it). Now, inflation is not a proven theory. Most astronomers believe that some form of inflation occurred, but we disagree on what form that inflation took. So, we can say that the idea of inflation is mildly controversial, but the exact details of that theory are fairly controversial.
Finally, we come to what happened before inflation. This is highly controversial -- the few theories that exist are fairly hand-wavey, and it is not yet possible to test these theories. Did the Universe come from some frothy quantum bubble in a larger-dimensional space? Maybe the Universe started when two branes of spacetime collided? Maybe this is where a Creator steps in? We really don't know.
So, in summary, the Big Bang is non-controversial, the theory of inflation is mildly controversial, and hypotheses about the pre-inflation universe are highly controversial.
Tomorrow, we'll look at science that is a bit more relevant to our everyday lives.
Wednesday, May 17, 2006
Today, the group of astronomers planning to build a large telescope, the Large-Scale Synoptic Telescope, announced that they had selected a site on which to build their telescope, a mountain in north-central Chile called Cerro Pachón.
The selection of a site is a vital part of building a telescope. It is not as simple as finding a dark mountain and bringing in the telescope parts, especially for modern, technologically-advanced telescopes. Some of the things we consider are the weather (How often is it crystal clear? What are the seasonal changes? How hard does the wind blow?), the seeing (how steady is the atmosphere?), the nearness of cities (causing light pollution and hurting our ability to see faint objects), the necessary infrastructure (Will we have to build 100 feet of roads or 100 miles of roads? Is high-speed Internet possible? What about water and food?), the altitude (if the altitude is too high, then we need to take care about the health of the astronomers and computers), and the overall economical and political situation (Will it cost too much to build? Is there endangered habitat we must be mindful of?)
These conditions, especially the last two, can change, so that a site that was deemed ideal (say, the dormant volcano Mauna Kea in Hawaii) may no longer be a workable solution due to past misunderstandings between Native Hawaiians, environmentalists, and astronomers.
Cerro Pachón already houses two telescopes, the Gemini 8-meter telescope and the SOAR 4-meter telescope, so from an economic and infrastructure point of view, it makes good sense to put the telescope there. We also have long-term experience with the weather there, and we understand the atmospheric stability. So today's site announcement makes sense.
How long until we can use this telescope? Only 6-10 years!
Tuesday, May 16, 2006
I am back at home after three weeks on the road, and I can finally get back to some work. I have a nice thick pile of mail to go through, and an even larger stack of email to read.
So, what now? Back in December I spent five nights at Kitt Peak taking data. I am finally starting to seriously examine those pictures, five months after they ended up on my disk. While that sounds like a long time, it is not that unusual. Analyzing data properly takes a lot of time, and there are always many things piled on an astronomer's to-do list. If the data were time-sensitive, like a supernova or a comet, we'd have looked at it right away. But since I am looking at galaxies as they were billions of years ago, it's acceptable to go a little slower and make sure everything is done just right.
Now I get to watch my computer chug away at almost 25 gigabytes of images for the next few days.
Friday, May 12, 2006
I spent yesterday and today on the campus of UC Santa Cruz, the institution where I earned my PhD. I still know most of the faculty here, as well as several of the students.
One of the graduate students, Kate Rubin, is giving a talk a project we have been working on today. It is part of the requirements here that every student complete a research project by the end of their second year and give an hour talk on the project. Kate is giving her talk today.
When I came to Santa Cruz in 1997, my class was the first class required to do these research projects and give these talks. It took a few years for the requirements to evolve and settle into the "modern" version, but I remember the nervous feeling very well. Kate will do fine, though. And then the weekend is here!
Thursday, May 11, 2006
This week it is off to sunny California, where it is actually foggy and colder than Tucson. So, please pardon that blogging has been even lighter than normal over the past few weeks. Next week things get back to "normal," whatever that is.
Tuesday, May 09, 2006
I wish I could claim responsibility for this picture of Comet Schwassmann-Wachmann 3's brightest fragment passing the Ring Nebula last Sunday night, but I was sitting in the Dallas-Ft. Worth Airport at the time. Instead, it was taken by Sheldon Faworski and Sean Walker and published online at Sky & Telescope's website.
This picture also covers quite a bit of space. The comet was about ten million miles away (one light-minute, meaning light from the comet took a minute to get to Earth), the Ring Nebula is about 2300 light-years away (or 50 million times further away), and the faint galaxy IC 1296 (above and to the right of the Ring Nebula in the picture) is about 70 million light-years away, about 1.5 trillion times further away than the comet.
This picture also represents three "phases" of my own journey in astronomy. My first astronomy project was in 1986 for my 6th-grade science fair, when I researched how comets interact with the sun. My PhD dissertation was on white dwarfs, the remains of dead stars. The Ring Nebula is a star in the process of dying, and the faint star at its center is on its way to becoming a white dwarf. And finally, my work in the past few years has been on distant galaxies, much more distant than IC 1296.
Monday, May 08, 2006
The British Ministry of Defence is releasing a study which finds that most, if not all, UFO sightings can be fully explained by natural phenomena, such as meteors, airplanes, weather, and so on. In other words, this 400+ page report concludes that there is no strong evidence that any UFOs are actually alien spacecraft.
As an astronomer, we are often asked about aliens and UFOs. And, to be honest, I don't know if extraterrestrial intelligence exists or not. But I feel pretty confident that alien spacecraft are not visiting the Earth. The challenges to long-distance space travel are far, far greater than most of us can imagine.
But I applaud the ministry for publically releasing their study. The U.S. Armed Forces have also studied the UFO phenomenon, but have not released their study. Personally, I would guess this is because many UFOs are military aircraft, both known and unknown. But this is just a guess. And, since the US does not release its studies, people continue to assume it must include aliens.
Friday, May 05, 2006
Greetings from Austin, the capital of Texas and the home of the University of Texas Longhorns. I am here to visit colleagues in the Astronomy Department and to scout out the town. Not counting layovers in the Dallas-Ft. Worth Airport, this marks my first trip to the Lone Star State.
The astronomy department here is quite large. Yesterday I met several faculty, postdocs, and students. We had good discussions on our work, with more on the way today. We also had a severe thunderstorm last night, with water streaming from the skies and quite a bit of wind. More storms today, and a street fair this weekend.
Wednesday, May 03, 2006
After two almost restful days at home, I am taking off to visit the Department of Astronomy at the University of Texas in Austin. UT Astronomy runs the McDonald Observatory (no relation to the fast food chain) in western Texas. UT also has many astronomers studying white dwarfs, including some of my collaborators.
This is my first, but likely not my last, visit to Austin. So if blogging is light, you'll know why.