Oisín
01-07-2009, 02:54 PM
Milky Way 'bigger than thought'
http://newsimg.bbc.co.uk/media/images/45349000/jpg/_45349756_lores.jpg
Andromeda was previously thought to be larger than the Milky Way
Our galaxy is much bigger than once thought, according to research presented at a major astronomy meeting this week.
The results suggest the Milky Way is roughly the same size as Andromeda, the largest galaxy in our local group.
What is more, it is moving 15% faster than earlier predictions.
The greater mass means that future collisions with nearby galaxies could happen sooner than thought, according to the researchers.
Mark Reid of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, US, and his colleagues made use of the Very Long Baseline Array (VLBA) to deduce the Milky Way's size and speed.
Dr Reid was speaking at the 213th American Astronomical Society (AAS) meeting in Long Beach, California.
The VLBA is a system of 10 radio telescopes scattered across and around North America that together allow unprecedented resolution in astronomy measurements.
This resolution, according to the CfA, is equivalent to being able to read a newspaper in Cairo from an armchair in Edinburgh.
By using the VLBA to measure the apparent shift of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts.
"These measurements use the traditional surveyor's method of triangulation and do not depend on any assumptions based on other properties, such as brightness, unlike earlier studies," said team member Karl Menten of the Max Planck Institute for Radio Astronomy in Bonn, Germany.
The results show that the Milky Way is about 15% wider than previously thought.
[Continue reading] (http://news.bbc.co.uk/1/hi/sci/tech/7813635.stm)
http://newsimg.bbc.co.uk/media/images/45349000/jpg/_45349756_lores.jpg
Andromeda was previously thought to be larger than the Milky Way
Our galaxy is much bigger than once thought, according to research presented at a major astronomy meeting this week.
The results suggest the Milky Way is roughly the same size as Andromeda, the largest galaxy in our local group.
What is more, it is moving 15% faster than earlier predictions.
The greater mass means that future collisions with nearby galaxies could happen sooner than thought, according to the researchers.
Mark Reid of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, US, and his colleagues made use of the Very Long Baseline Array (VLBA) to deduce the Milky Way's size and speed.
Dr Reid was speaking at the 213th American Astronomical Society (AAS) meeting in Long Beach, California.
The VLBA is a system of 10 radio telescopes scattered across and around North America that together allow unprecedented resolution in astronomy measurements.
This resolution, according to the CfA, is equivalent to being able to read a newspaper in Cairo from an armchair in Edinburgh.
By using the VLBA to measure the apparent shift of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts.
"These measurements use the traditional surveyor's method of triangulation and do not depend on any assumptions based on other properties, such as brightness, unlike earlier studies," said team member Karl Menten of the Max Planck Institute for Radio Astronomy in Bonn, Germany.
The results show that the Milky Way is about 15% wider than previously thought.
[Continue reading] (http://news.bbc.co.uk/1/hi/sci/tech/7813635.stm)