For the new year 2008 ...
anyone up for the long count?
anyone up for the long count?I would like at this time, the beginning of a new year, to review some numbers. These numbers identify us, the inhabitants of earth, at a certain address in the Milky Way Galaxy:
- 226 million years
- 135 miles per second
- 100 billion stars
- 26,000 light years
- 6 trillion miles per light year
- one ten- thousandth the diameter of a human hair held at arms length
- one-600,000th of what could be detected with the human eye
- 2.6 million times more massive than the sun
- 1,100 miles per hour
- 67,000 miles per hour
- 486,000 miles per hour
Radio astronomers measure sun's orbit around Milky Way, By PAUL RECER
Associated Press
June 01, 1999, 09:40 p.m. Article retrieved today: 01/03/08
CHICAGO -- Astronomers focusing on a star at the center of the Milky Way say they have measured precisely for the first time how long it takes the sun to circle its home galaxy: 226 million years. The last time the sun was at this exact spot of its galactic orbit, dinosaurs ruled the world.
Using a radio telescope system that measures celestial distances 500 times more accurately than the Hubble Space Telescope, astronomers plotted the motion of the Milky Way and found that the sun and its family of planets were orbiting the galaxy at about 135 miles per second.
That means it takes the solar system about 226 million years to orbit the Milky Way and puts the most precise value ever determined on one of the fundamental motions of the Earth and its sun, said James Moran of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
"Our new figure of 226 million miles is accurate to within 6 percent," Mark Reid, a Harvard-Smithsonian astronomer and leader of the team that made the measurements, said in a statement.
The sun is one of about 100 billion stars in the Milky Way, one of billions of ordinary galaxies in the universe.
The Milky Way is a spiral galaxy, with curving arms of stars pinwheeling out from a center.
The solar system is about halfway out on one of these arms and is about 26,000 light years from the center. A light year is about 6 trillion miles.
Reid and his team made the measurement using the Very Long Baseline Array, a system of 10 large radio-telescope antennae placed 5,000 miles across the United States, from the U.S. Virgin Islands to Hawaii.
Working together as a single unit, the antennae can measure motions in the distant universe with unprecedented accuracy.
The accuracy is such that the VLBA can look at a bit of sky that has an apparent size one ten- thousandth the diameter of a human hair held at arms length.
For their solar system measurement, the astronomers focused on Sagittarius A, a star discovered two decades ago to mark the Milky Way's center. Over a 10-day period, they measured the apparent shift in position of the star against the background of stars far beyond.
The apparent motion of Sagittarius A is very, very small, just one-600,000th of what could be detected with the human eye, the astronomers said.
Reid said the measurement adds supports to the idea that the Milky Way's center contains a supermassive black hole.
"This ... strengthens the idea that this object, much smaller than our own solar system, contains a black hole about 2.6 million times more massive than the sun," Reid said in a statement.
Moran said the new measurement of the solar system orbit adds new accuracy to a fundamental fact of the universe: Everything is moving constantly.
The Earth rotates on its axis at about 1,100 miles an hour, a motion that creates day and night... [and weather].
The Earth orbits the sun at about 67,000 miles an hour, a motion that takes one year.
The sun circles the Milky Way at a speed of about 486,000 miles per hour. And every object in the universe is moving apart from the other objects as the universe expands at a constantly accelerating rate.
Associated Press
June 01, 1999, 09:40 p.m. Article retrieved today: 01/03/08
CHICAGO -- Astronomers focusing on a star at the center of the Milky Way say they have measured precisely for the first time how long it takes the sun to circle its home galaxy: 226 million years. The last time the sun was at this exact spot of its galactic orbit, dinosaurs ruled the world.
Using a radio telescope system that measures celestial distances 500 times more accurately than the Hubble Space Telescope, astronomers plotted the motion of the Milky Way and found that the sun and its family of planets were orbiting the galaxy at about 135 miles per second.
That means it takes the solar system about 226 million years to orbit the Milky Way and puts the most precise value ever determined on one of the fundamental motions of the Earth and its sun, said James Moran of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
"Our new figure of 226 million miles is accurate to within 6 percent," Mark Reid, a Harvard-Smithsonian astronomer and leader of the team that made the measurements, said in a statement.
The sun is one of about 100 billion stars in the Milky Way, one of billions of ordinary galaxies in the universe.The Milky Way is a spiral galaxy, with curving arms of stars pinwheeling out from a center.
The solar system is about halfway out on one of these arms and is about 26,000 light years from the center. A light year is about 6 trillion miles.
Reid and his team made the measurement using the Very Long Baseline Array, a system of 10 large radio-telescope antennae placed 5,000 miles across the United States, from the U.S. Virgin Islands to Hawaii.
Working together as a single unit, the antennae can measure motions in the distant universe with unprecedented accuracy.
The accuracy is such that the VLBA can look at a bit of sky that has an apparent size one ten- thousandth the diameter of a human hair held at arms length.
For their solar system measurement, the astronomers focused on Sagittarius A, a star discovered two decades ago to mark the Milky Way's center. Over a 10-day period, they measured the apparent shift in position of the star against the background of stars far beyond.The apparent motion of Sagittarius A is very, very small, just one-600,000th of what could be detected with the human eye, the astronomers said.
Reid said the measurement adds supports to the idea that the Milky Way's center contains a supermassive black hole.
"This ... strengthens the idea that this object, much smaller than our own solar system, contains a black hole about 2.6 million times more massive than the sun," Reid said in a statement.
Moran said the new measurement of the solar system orbit adds new accuracy to a fundamental fact of the universe: Everything is moving constantly.
The Earth rotates on its axis at about 1,100 miles an hour, a motion that creates day and night... [and weather].
The Earth orbits the sun at about 67,000 miles an hour, a motion that takes one year.
The sun circles the Milky Way at a speed of about 486,000 miles per hour. And every object in the universe is moving apart from the other objects as the universe expands at a constantly accelerating rate.
Want some down on earth measurement? To compare some of the numbers -- Sound travels through air at "the speed of sound." Officially, the speed of sound is 331.3 meters per second (1,087 feet per second) in dry air at 0 degrees Celsius (32 degrees Fahrenheit). At a temperature like 28 degrees C (82 degrees F), the speed is 346 meters per second.
As you can see, the speed of sound changes depending on the temperature and the humidity; but if you want a round number, then something like 350 meters per second and 1,200 feet per second are reasonable numbers to use. So sound travels 1 kilometer in roughly 3 seconds and 1 mile in roughly 5 seconds.
When you see the flash of a lightning bolt, you can start counting seconds and then divide to see how far away the lightning struck. If it takes 10 seconds for the thunder to roll in, the lightning struck about 2 miles or 3 kilometers away. With bolt temperatures hotter than the surface of the sun and shockwaves beaming out in all directions, lightning is a lesson in physical science and humility.
Do you agree? That would be enough numbers to identify us in the Milky Way. Info retrieved at:
and
No comments:
Post a Comment