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Ephemeris: 04/29/2025 – Using the Sun as a telescope

April 29, 2025 Comments off

This is Ephemeris for Tuesday, April 29th. Today the Sun will be up for 14 hours and 10 minutes, setting at 8:45, and it will rise tomorrow at 6:33. The Moon, 2 days past new, will set at 11:56 this evening.

One idea of a telescope I find very fantastic. This is a telescope that uses the Sun and its mass curving spacetime to alter the path of light from a distant object to act like a lens in a telescope. This is called gravitational lensing. The length of this telescope would have to be about 542 times the earth’s distance from the Sun, 542 astronomical units. In the 48 years since Voyager 1 was launched it has achieved only about 1/3 of that distance. What would be the use of this telescope would be to image exoplanets. So far exoplanets, if they are visible at all, don’t even cover a single pixel in even our largest telescopes. The problems are huge, starting with gravitational lenses don’t bend light the same way as optical ones do.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Using the gravitational field of the sun as a telescope
This is a diagram of how using the gravitational field of the Sun as a telescope might work in observing a star with an exoplanet. This diagram is from NASA via an article in Universe Today by Paul Sutter. The small satellite clusters shown in the diagram actually act as pixels as they measure the brightness of the Einstein ring that the star and planet produce. The image is built up from all these satellites. The tiny disk of the Sun itself must be blocked. I find it quite improbable that this particular kind of system could ever be created. It would cost billions of dollars to actually do it, and take a long time for the satellites to get out there, and be able to only obsesrve one star and its exoplanets. This “telescope” can’t be pointed at anything else. I find it an interesting exercise to think about, but I doubt anything like this could ever be created. Of course that’s an opinion of an old amateur astronomer.

Here are some sources of additional information on this topic:

https://www.universetoday.com/articles/how-can-the-sun-become-a-telescope
https://www.livescience.com/space/the-sun/could-we-turn-the-sun-into-a-gigantic-telescope
https://nasaspacenews.com/2025/04/see-alien-planets-in-4k-the-suns-gravitational-lens-explained/
https://news.stanford.edu/stories/2022/05/gravity-telescope-image-exoplanets
https://www.space.com/sun-gravity-could-help-observe-exoplanets-in-detail

Categories: Concepts, Ephemeris Program, Exoplanets, Telescope Tags: