Archives of Ask A Scientist!
About "Ask A Scientist!"
On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.
Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.
In fact, while today we know planets exist around two dozen or so stars, none have actually been "seen" in the usual sense. Instead, "extra solar planets" have been found by the same method used in the 1840's to discover the planet Neptune. By figuring out that a more distant but then unknown planet was responsible for oddities in the observed motion of Uranus, astronomers knew where to look for the new planet and quickly found Neptune.
Planets, like all masses in the universe, exert a gravitational pull on their parent stars, causing the stars to move slightly. Since the Sun contains more than 99% of the mass in the Solar System, it has a much greater gravitational effect on the planets than they do on it. Nonetheless, the planets do tug on the Sun and cause it to move slightly, at about 12 meters per second. In contrast, the Earth moves much faster, about 30 kilometers per second because of the Sun's pull on it. If other stars show motions similar to the Sun's, then astronomers can infer that those stars too are being tugged on by their own "planetary systems" even though we can't actually see the planets.
In 1992, two radio astronomers monitoring the motion of a very dense, compact and rapidly spinning star called a pulsar noticed that the star was making a series of tiny motions that were best explained if the star had three planets in its planetary system. Two of the planets are similar in mass to the Earth while the third one is quite a bit smaller, more like our Moon.
Since then, astronomers have been able to detect one (or sometimes more) planets around about 20 nearby Sun-like stars. Because it is much easier to detect massive planets like Jupiter, most of the newly discovered planets are much bigger than the Earth -- but we suspect that there are lots more planets that we haven't yet found. As powerful new telescopes improve our ability to "see" faint, small objects, we soon ought to get a glimpse of what those planets look like and to learn how they might be different from the nine familiar ones in our own Solar System.
- Where do tornadoes come from?
- How many earths will fit in the sun?
- Does the mass of the Earth increase with the increasing population? If not, why not?
- Why do some scientists believe Pluto is not a planet? The dictionary defines a planet as "A non-luminous celestial body illuminated by light from a star, such as the sun, around which it rotates." Doesn't Pluto meet these conditions?
- Why does each snowflake have a different shape?
- How can the sun burn without oxygen in space? If there is oxygen in space why do astronauts need oxygen?
- Why do stars twinkle?
- What causes the earth to rotate and why?
- Does the moon have earthquakes/moonquakes?
- What are the possibilities that there is another form of life in the universe?