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wrote...
A month ago
Sorry for late reply, had to build new pc...  

Or do you mean Venus?  We don't have probes that skim past either.
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wrote...
Staff Member
A month ago
Sorry for late reply, had to build new pc... Or do you mean Venus? We don't have probes that skim past either.

From Wikipedia we learn that there have been numerous unmanned missions to Venus. In fact, ten Soviet probes have achieved a soft landing on the surface, with up to 110 minutes of communication from the surface, all without return. Launch windows occur every 19 months.

Furthermore, these days this can be done without any flyby probes. The Arecibo Observatory is a radio telescope in the municipality of Arecibo, Puerto Rico. It's huge, and can send signals that pass through both our planet’s atmosphere and the atmosphere of Venus, where they hit the surface and bounced back to be received by the 100-meter Green Bank Telescope in a process known as bistatic radar.
Source https://en.wikipedia.org/wiki/Observations_and_explorations_of_Venus#Observation_by_spacecraft

https://astronomynow.com/2015/03/10/venus-revealed-in-high-resolution-radar-images-from-earth/
- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education
wrote...
A month ago
Sorry for late reply, had to build new pc... Or do you mean Venus? We don't have probes that skim past either.
From Wikipedia we learn that there have been numerous unmanned missions to Venus. In fact, ten Soviet probes have achieved a soft landing on the surface, with up to 110 minutes of communication from the surface, all without return. Launch windows occur every 19 months. Furthermore, these days this can be done without any flyby probes. The Arecibo Observatory is a radio telescope in the municipality of Arecibo, Puerto Rico. It's huge, and can send signals that pass through both our planet’s atmosphere and the atmosphere of Venus, where they hit the surface and bounced back to be received by the 100-meter Green Bank Telescope in a process known as bistatic radar.
Thank you, that's very interesting, so now I'm wondering did any of these unmanned craft sent to Venus send a radar signal to the Sun to get it's distance from there before relaying that info back to Earth?
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wrote...
Staff Member
A month ago
The strength of the radar signal falls rapidly with distance so for objects within the Solar System we are dealing with very faint reflected signals. That isn't a problem with objects like Venus because with suitable signal processing we can extract the radar reflection from the background noise. The problem with the Sun is that it's a (very) strong emitter of radio waves and this black body background completely swamps the radar reflection.
- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education
wrote...
A month ago
The strength of the radar signal falls rapidly with distance so for objects within the Solar System we are dealing with very faint reflected signals. That isn't a problem with objects like Venus because with suitable signal processing we can extract the radar reflection from the background noise. The problem with the Sun is that it's a (very) strong emitter of radio waves and this black body background completely swamps the radar reflection.
Exactly, I totally agree!  Any signal sent to the Sun even from Venus (forget Earth) wouldn't get there at all intact and so nothing would be reflected.  So how are they able to calculate the distance of the Sun even with what we have now, never mind with what we had decades or centuries ago.  If however I've misunderstood something, my apologies.
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wrote...
Staff Member
A month ago Edited: A month ago, duddy
No need to apologise! That's how math helps us understand the world better. We can extrapolate data from simple, yet complex calculations. For example, Einstein predicted that blackholes existed well before it was accepted in the scientific world, and he did this strictly through his knowledge of physics and math. He didn't have radars, he didn't use probes, and it was only until this year that they were visually able to see one.

If you have any follow up questions, let me know
- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education
wrote...
A month ago
This just about explains it for me, thank you Slight Smile
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