Seeing the sun at night

It is technically possible to obtain an image of the Sun through the Earth, and it has already been done.

Neutrinos, elementary particles similar to electrons but lighter and without an electrical charge, are constantly emitted from the Sun’s core, and it has been possible to get a real image of our star by detecting them with a giant underground tank of 50,000 tonnes of water, over the course of 503 days.

Neutrinos only interact with gravity in an incredibly weak way due to their almost negligible mass, and with weak nuclear interaction, which is responsible for radioactive decays. For this reason, detecting them is not an easy task.

The image above was obtained by recording the light pulses of Cerenkov radiation. This is emitted when one of the electrons in water molecules interacts with a neutrino and is accelerated by it to speeds greater than the speed of light in water (but less than the speed of light in vacuum), to then radiate photons.

In short, it is the light equivalent of a sonic boom, caused by the interaction with neutrinos.