How much in the past do we see these planets?

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SUMMARY

The HR 8799 star, located 129 light-years away, is observed through thermal emissions from its planets. These emissions travel at the speed of light, indicating that the infrared images captured reflect the planets' appearance as they were 129 years ago. This confirms that infrared radiation, being a form of electromagnetic radiation, behaves similarly to visible light in terms of travel speed and temporal representation.

PREREQUISITES
  • Understanding of electromagnetic radiation, specifically infrared and visible light.
  • Basic knowledge of astronomical distances and light-years.
  • Familiarity with the concept of light speed in a vacuum.
  • Awareness of thermal emissions and their significance in astrophysics.
NEXT STEPS
  • Research the properties of infrared radiation and its applications in astronomy.
  • Explore the concept of light-years and its implications for astronomical observations.
  • Investigate the HR 8799 star system and its planets in detail.
  • Learn about the techniques used to capture and analyze thermal emissions from celestial bodies.
USEFUL FOR

Astronomers, astrophysics students, and anyone interested in the study of exoplanets and their thermal characteristics.

Dreksler
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TL;DR
This infrared image shows planets that are orbiting a star called HR 8799, since these are thermal emissions does it still mean planets here that we see are 129 years in the past?
The HR 8799 star is 129 light-years away from us, in this image we can see thermal emissions coming from these planets. Do these emissions move at the speed of light? If so does it mean that what we are seeing in this image is how the planets looked like in infrared 129 years in the past?
 

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Infrared is electromagnetic radiation, just like visible light (it just has a different wavelength), so yes and yes.
 
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Thank you!
 
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