The exact number of planets in the universe is still unknown, as our current scientific knowledge is limited to what we have observed and discovered so far. However, considering the vastness of the universe, it is highly probable that there are more planets than the grains of sand on Earth.
To put things into perspective, there are estimated to be billions of galaxies in the observable universe, and each galaxy can contain billions or even trillions of stars. Many of these stars are known to have planets orbiting them, based on observations and discoveries from telescopes like the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS).
Given the immense number of stars and galaxies in the universe, it is reasonable to infer that the number of planets is likely to be extraordinarily large. Even if we consider a conservative estimate of just a few planets per star on average, the total number of planets would be astronomical.
Comparatively, the number of grains of sand on Earth is estimated to be in the order of magnitude of 10^18 (1 followed by 18 zeros). While this is an incredibly large number, it is minuscule compared to the potential number of planets in the vastness of the universe.
Therefore, based on current scientific understanding, it is plausible that there are indeed more planets in the universe than the grains of sand on Earth. However, due to the immense scale and our limited knowledge of the cosmos, it is challenging to provide an exact count.