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(Babak Tafreshi / Science Source)
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“Contact” is by far one of my most favorite books-turned-movie in my childhood. The idea that a theologian could fall in love with a scientist when their diverging, fundamental beliefs made the very possibility impossible is moving. Even more touching was the openness of wealthy nations in the movie to pool their resources for a risky space expedition in the name of scientific curiosity.
Last week, the scientific community celebrated a similar international collaboration, the inauguration of the Atacama Large Millimeter/submillimeter Array, or ALMA, the largest array of radio telescopes in the world. Located 5000 meters above sea level, ALMA combines large radio antennas from the European Southern Observatory (ESO), the National Astronomical Observatory of Japan, and the National Radio Astronomy Observatory of North America.
ALMA will allow scientists to observe the formation of stars and galaxies with more strength than any other radio telescope system in the world.
Scientists use optical telescopes, like the Hubble, to observe the visible light that objects project. However, all objects, both on Earth and in space, project radio-frequency waves that can be detected by large antennas. These antennas, called radio antennas, look like satellite dishes, but they are a lot larger. Their larger sizes allow them to pick up radio signals from space, which are a lot weaker than signals that are concentrated and sent to Earth by satellite dishes in space. Of the 66 antennas in the ALMA array, 54 measure 12 meters across, and 12 measure seven meters across. Together, they function as a single, large telescope.
The resolution of a radio telescope is defined by the length of the incoming wave and the width of the antenna dish. The smaller the incoming wave and the larger the dish, the higher the resolution. Radio telescopes can work in groups to obtain an even higher resolution than if one were working alone.
Although the collaboration started in the 1990s, it wasn’t until recently that ESO delivered the final radio antennas to round out the group. These last ones haven’t yet been installed into the fully-functioning installation just yet, but they expect to be installed by the end of this year. The 66-dish ALMA project will beat out the National Science Foundation-funded PAPER (Precision Array for Probing the Epoch of Reionization) installation, which currently operates 62 antennas in South Africa.
Here are some cool photos.
On celebrating the inauguration now rather than at the end of the project.
ALMA means “soul” in Spanish.
“… the largest science project ever where nobody was in charge.” – Ethan Schreier, ALMA operations