No, you don't know it. You heard it.
Your data was passed on to who knows how many people and played with until it reached you. You're not a primary source, nor a secondary source. You might even be 10 levels below that.
Not to mention the conclusion about the formation of the grand canyon is, at best, guesswork. There's no way to know what really happened, and no way to find out how accurate your conclusion is. Millions of years have passed, anything could have happened.
How is this any better than imagination or hearsay?
I'm not saying you or the other side is wrong or right. There's a chance your conclusion is right. But the way you're arguing is definitely wrong and will cause you issues if you continue like that.
The idea that anything that has occurred in the distant past can only be contemplated by imagination or worse still pure guesswork illustrates a lack of understanding of how science works.
For example in the 1940s a really clever dude made the prediction if there was a Big Bang it would it would leave a background radiation at a temperature of around 5K.
In the 1960s the background radiation was discovered and found to have a temperature of 2.7K, hence the prediction was quite accurate.
So how did this prediction come about.
(1) In the early part of the 20th century it was found distant galaxies recede from each other.
The further the galaxies were from the observer the faster they receded.
(2) From this data, four very smart dudes independently came up with the theory the universe is expanding and could be described by a piece of mathematics known as a metric.
(3) When this metric was plugged in Einstein's theory of general relativity field equations, mathematical equations were generated which could define the rate of expansion of the universe.
(4) Applying thermodynamics, the early universe must have been extremely hot and expansion cooled the universe.
(5) Around the same time frame for the development of the Big Bang expansion theory, scientists were uncovering the nature of the atom being composed of a positive charged nucleus and negative charged electrons and the high temperatures of the early universe would result in free electrons and nuclei.
(6) The existence of a background radiation was predicted that as the universe cooled, free electrons became bonded to proton nuclei to form the primeval hydrogen.
Prior to this photons were being scattered by electrons and the universe was opaque.
The radiation background was the last stage before the universe became transparent to light.
(7) This last stage was predicted when the universe had expanded by a factor of around 1100X and since the temperature is inversely proportional to this expansion factor, the temperature of the background radiation as it is today was predicted to be 5K compared to the observed value of 2.7K.
This is clearly in stark contrast to the use of one's imagination in describing an event well before humans came on the scene.
