Hubble telescope finds a planet where it rains glass

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Discussion Overview

The discussion centers around the discovery of the exoplanet HD 189733b, which is reported to have a deep blue color and extreme weather conditions, including the possibility of glass rain. Participants explore the methods used by astronomers to determine the planet's color and characteristics, as well as the limitations of the Hubble Space Telescope in resolving distant objects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants highlight that the reported image of the planet is an artist's impression, noting that Hubble's resolution is insufficient to directly resolve an object 63 light years away.
  • Others question how astronomers can study an object that is only about 1/1000 of a Hubble pixel across, indicating skepticism about the methods used.
  • A participant cites a NASA source explaining that Hubble's Space Telescope Imaging Spectrograph measured changes in light from the planet as it passed behind its star, leading to conclusions about its color based on the light spectrum.
  • Details from a research paper are shared, including the observation that blue light was missing when the planet was obscured, suggesting it has a blue color.

Areas of Agreement / Disagreement

Participants express skepticism about the imaging capabilities of Hubble regarding distant planets, with some agreeing on the limitations of resolution while others focus on the methods used to infer the planet's color. The discussion does not reach a consensus on the validity of the findings.

Contextual Notes

Limitations include the dependence on indirect measurements and the challenges of interpreting data from such distant objects, as well as the reliance on artist's impressions for visual representation.

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http://www.cnn.com/2013/07/11/world/space-blue-planet/index.html?hpt=hp_t1

Astronomers have found a deep azure blue planet orbiting a star 63 light years away -- the first time they've been able to determine the actual color of a planet outside our solar system, NASA and the European Space Agency said Thursday.
The planet, known as HD 189733b, is a gas giant with a daytime temperature of 2,000 degrees Fahrenheit where it possibly rains liquid glass sideways amid 4,500 mph winds, NASA says.

130711222217-01-blue-planet-story-body.jpg
 
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That image is an artist's impression. Hubble doesn't have anywhere close to the resolution to resolve a planet 63 light years away. That planet is about 1/1000 of a Hubble pixel across.
 
D H said:
That image is an artist's impression. Hubble doesn't have anywhere close to the resolution to resolve a planet 63 light years away. That planet is about 1/1000 of a Hubble pixel across.

Good call! How can they study something that is 1/1000 of a Hubble pixel?
 
From http://www.nasa.gov/content/nasa-hubble-finds-a-true-blue-planet/#.UeAYkxZiigw:
Hubble's Space Telescope Imaging Spectrograph measured changes in the color of light from the planet before, during and after a pass behind its star. There was a small drop in light and a slight change in the color of the light. "We saw the light becoming less bright in the blue but not in the green or red. Light was missing in the blue but not in the red when it was hidden," said research team member Frederic Pont of the University of Exeter in South West England. "This means that the object that disappeared was blue."​

The paper on this was just published in The Astrophysics Journal Letters.

Evans, T. et al., The deep blue color of HD 189733b: albedo measurements with HST/STIS at visible wavelengths, 2013 ApJ 772 L16.
Official paper: http://iopscience.iop.org/2041-8205/772/2/L16
Pre-publication version: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1311.pdf.
 
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