by Playfuls Staff |
5th August 2006
Astronomers never cease to amaze us with their…wrong calculations. First they hypothesized that the speed of light has slowed down. Now they find the Hubble constant is, of course, wrong.[more]
In 2000, a couple of astronomers implied that the speed of light has slowed down in the last two billion years, which could have tremendous consequences for the entire astrophysics.
Now, a team of astronomers from Ohio State University are challenging another Universal constant, discovered and theoretically described by the great Edwin Hubble.
The Hubble constant is an estimate of the universe's dimensions and age. It has been used for more than 80 years to calculate the distance of different objects from Earth.
The constant uses a series of measurements, including differences in light intensity and changes in the "red shift," which measures how far the light from a distant star is shifted toward the red end of the light spectrum. The greater the red shift, the farther away the object is and the faster it is traveling.
According to the team of scientists from the Ohio State University the Hubble constant is inaccurate by an estimated quantity of 15%. This means that our Universe could be 15 percent older and at least 15 percent bigger than previous measurements have reported.
What does that mean in numbers? 46 billion light-years to 78 billion light-years in “diameter”... And if that is not impressive, just think that our “teenage” Universe could actually approach maturity: from actual estimates of around 13.7 billion years old the age could increase to around 16 billion years.
"The Hubble constant used to be the one parameter that we knew pretty well. Now it's lagging behind," said Krzysztof Z. Stanek, a coauthor of a paper describing the new work, scheduled to appear in the Astrophysical Journal.
Peter Eisenhardt, a scientist at the Jet Propulsion Laboratory in La Cańada Flintridge specializing in galaxy evolution, called the paper a "pretty solid piece of work."
The team's study focused on two stars in the Traingulum Galaxy that eclipse one another every five days. Using new methods the astronomers measured the temperature, light and velocity of these star's intrinsic luminosity. Their method was developed over a decade and equipment included new telescopes that scanned in the infrared range.
The new results indicate the galaxy's distance from Earth as 3.14 million light years away whereas measurements based on Hubble law had said 2.6 million light years – a difference of nearly half a million light years. The difference has suggested that other measurements must be similarly imprecise.
Krzysztof Z. Stanek said the scientists only tried to find a simpler and “independent measure of distance- a single step that will one day help with measuring dark energy and other things."
But he also warned that it would be exaggerated and premature to change the model of the universe based on this single study. He also said interstellar dust might be interfering with the light from Triangulum, making it appear farther away than it really is. The Ohio team took dust into consideration but used a slightly different method to estimate its impact on distance calculations, Eisenhardt said.
