Astronomers use radio emissions from distant galaxy to observe asteroid


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The wonders of science: Astronomers have successfully used the faint radio emissions from very distant galaxy to roughly determine the shape and size of a nearby asteroid.

In an unusual observation, astronomers used the National Science Foundation’s Very Long Baseline Array (VLBA) to study the effects on radio waves coming from a distant radio galaxy when an asteroid in our Solar System passed in front of the galaxy. The observation allowed them to measure the size of the asteroid, gain new information about its shape, and greatly improve the accuracy with which its orbital path can be calculated.

When the asteroid passed in front of the galaxy, radio waves coming from the galaxy were slightly bent around the asteroid’s edge, in a process called diffraction. As these waves interacted with each other, they produced a circular pattern of stronger and weaker waves, similar to the patterns of bright and dark circles produced in terrestrial laboratory experiments with light waves. “By analyzing the patterns of the diffracted radio waves during this event, we were able to learn much about the asteroid, including its size and precise position, and to get some valuable clues about its shape,” said Jorma Harju, of the University of Helsinki in Finland.

The amount of information is not great, and there is an enormous amount of uncertainty in the data. Nonetheless, this is an amazing and fascinating observation.

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4 comments

  • Col Beausabre

    Who needs plastic guns when you can make metal ones ?!

  • Ryan Lawson

    This illustrates why I love science and human ingenuity! We always find elegantly simple ways to do things that previously seemed impossible. If the entire universe is backlit by microwaves doesn’t that mean with a big enough array of microwave telescopes you could eventually find all kinds of objects not detectable any other way?

  • Localfluff

    Astronomers are hunting for the first ever Oort Cloud Object ever to be detected in GAIA data, using diffraction or microlensing of a background star. Using diffraction in radio frequences and from galaxies might have big potential. The VLBI is however spanning the entire Earth using interferometry. The Russian 10 meter space radio telescope SPEKTR-R that orbits Earth out to near one Lunar distance is also hooked up to it. So it doesn’t seem to be an easy thing to do. The expanding telescope arrays of ALMA and SKA might come in handy in the coming years.

  • Col Beausabre

    SPEKTR…..Of course the Rooshans would name it SPECTRE, Mr Bond

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