Kepler Telescope Views Single Point in Space 4.2ly Away

In summary: I find that hard to believe but, as they say, Nature doesn't have to make sense to us.In summary, astronomers are able to observe planets that are 4.2 light years away using the Kepler space telescope, even though its resolution is not enough to directly see the planet. Instead, they use the technique of measuring the intensity of a star's light, which can be affected by a planet passing in front of it. Another method is through measuring the Doppler shift of a star's velocity, which can indicate the presence of an orbiting planet. Despite limitations in resolution, new techniques like speckle interferometry continue to push the boundaries of what can be observed in the vast expanse of space.
  • #1
bill ginger
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Astronomers are viewing a single point in space (.1 arcseconds), using the Kepler space telescope but to view a planet 4.2 light years from the Earth that would require a planet with a diameter of more than ten times the diameter of our solar system.
 
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  • #2
Do you have a question or did you just need to let us know about that?
 
  • #3
The question seems to be: how is it possible to observe a planet when your instrument has insufficient resolution.

The answer lies in the technique used - the planets observed by Kepler are not directly resolved, but their presence is inferred from stellar light curves. That is, the CCD camera on the spacecraft collects light from a star, measuring its intensity. When a planet transits in front of the star, it obscures some of this light. The size and orbit of the planet can be determined from the depth and duration of the dip in luminosity (i.e. 'light curves').

More on the method can be found here:
http://kepler.arc.nasa.gov/Mission/QuickGuide/howKeplerFindsPlanets/
 
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  • #4
There is another technique. Kevin Apps, credited with finding the first exoplanet (Planet Kevin) told a group of my students that they used Doppler shift due to the Wobble, as a large planet orbits a star. I seem to remember that it required Jupiter sized planets.
 
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To which physical point do you refer? The star-planet separation?
 
  • #6
DrSteve said:
To which physical point do you refer? The star-planet separation?
The wobble in relative star/Earth velocity gives a measurable (apparently) shifting on wavelength (presumably of some sharp absorption lines).
Afair, his talk was given around ten years ago. I guess the method would have an advantage in that the effect would be detectable even without a transit of the planet. It always bothers me that we must be missing a significant number of planets that have orbits which don't present us with a transit.
 
  • #7
sophiecentaur said:
The wobble in relative star/Earth velocity gives a measurable (apparently) shifting on wavelength (presumably of some sharp absorption lines).
Afair, his talk was given around ten years ago. I guess the method would have an advantage in that the effect would be detectable even without a transit of the planet. It always bothers me that we must be missing a significant number of planets that have orbits which don't present us with a transit.

I understand the Doopler shift method but still don't know which physical separation you refer to in your original post.
 
  • #8
DrSteve said:
I understand the Doopler shift method but still don't know which physical separation you refer to in your original post.
?? The relevant measurement was of the change of relative velocity of the Star (the source) and the Earth (receiver). The variation in velocity (amplitude and frequency) and the 'known' mass of the star (from other data such as absolute magnitude and spectrum) would give the probable mass and orbital radius of the orbiting planet. He was well chuffed with himself about that - but then, so would anyone be. Thing was, he didn't invent the technique, he made a calculation to suggest the part of the galaxy in which to look. They looked . . . . and they found.
 
  • #9
Then the .1 arcsec separation mentioned in the original post has no bearing on anything. Did you have a question that you wanted to pose to the forum?
 
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  • #10
DrSteve, you're confusing sophiecentaur with the OP, who has absconded.
 
  • #11
Bandersnatch said:
DrSteve, you're confusing sophiecentaur with the OP, who has absconded.
Thanks much. Responding via my cell phone leaves much to be desired.
 
  • #12
DrSteve said:
Thanks much. Responding via my cell phone leaves much to be desired.

So I'm not the only one. The small screen is like viewing the world through a toilet roll tube.
We already decided that resolution is just no enough. I wonder if it will ever be.
 
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  • #13
It's difficult, if not impossible, to get a sweeping overview of an online conversation from a phone, especially if a thread gets hijacked.
 
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  • #14
Bandersnatch said:
DrSteve, you're confusing sophiecentaur
That's not hard to do! :smile:
 
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  • #15
Speckle interferometry can tease amazing details from an otherwise apparently random collection of photons.
 
  • #16
Chronos said:
Speckle interferometry can tease amazing details from an otherwise apparently random collection of photons.
Yes. Mr Shannon implies that, given time, there is no limit to the possible resolving power.
 

What is the Kepler Telescope?

The Kepler Telescope is a space-based telescope launched by NASA in 2009 to search for exoplanets, or planets outside of our solar system, by observing changes in the brightness of stars.

How far away is the single point in space that the Kepler Telescope is viewing?

The single point in space that the Kepler Telescope is currently viewing is approximately 4.2 light years away. This is equivalent to about 25 trillion miles.

Why is the Kepler Telescope only viewing a single point in space?

The Kepler Telescope was designed to focus on a specific patch of the sky, known as the Kepler field, to observe a large number of stars for an extended period of time. This allows for more accurate and consistent data collection for studying exoplanets.

What does it mean for a planet to be 4.2 light years away?

A planet that is 4.2 light years away is a considerable distance from Earth. It would take light, which travels at a speed of 186,282 miles per second, 4.2 years to reach this planet. This distance is too far for current technology to reach, but it is relatively close in terms of the vastness of the universe.

What can we learn from the Kepler Telescope's view of this single point in space?

The Kepler Telescope's view of this single point in space allows us to gather data and study the stars and any potential exoplanets in that region. This data can provide insights into the formation and evolution of planets and potentially lead to the discovery of new exoplanets.

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