The Universe's Secret

Question

To find the universe's secret, first solve the Sudoku variant with #s 1-7 only.

No number may be repeated on any diagonal. No numbers go in the squares with red or green dots.

Then use the solution and the red/green squares to find the universe's secret.

The accepted answer will show detail and be well-articulated.

_{I'm feeling generous. The accepted answer will receive 500 bonus rep points.}

Answer 1

Following from @justhalf and @Jafe’s answers,

We now have the 9x9 sudoku solved using the numbers 1-7, and can now look at the black, unfilled squares. Sum up the values of the digits orthogonally adjacent to each black box, and add/subtract the number of dots lit up, depending on whether they are colored green/red, respectively. Convert to letters (using A1Z26) and read them in reading order to get the answer: THE LAW OF ATTRACTION.

Answer 2

Partial answer. I have the answer to the sudoku but still stuck on the dot puzzle.

Sudoku solution

The 6 only has one possible place it can go in the top-left box. After that, there's only one spot for a 6 on the seventh row. Every 6 is placed pretty quickly based on that.



Putting a 5 in row 1 column 4 would make it impossible to put a 5 anywhere in the top-left box. So the 5 can't be there, leaving only one other place it can go. That forces the 5 in the top-left box.



The 5 in the bottom-right box must be in column 9, which means the 5 in the mid-right box must be in column 8. Only one place where it fits. From there it's simple to place the rest of the 5's.



Only one place where a 2 goes in the bottom-right box now. That gives us the 2 in the central box, which in turn forces the 2 into place in column 2. After that there's only one option for the 2 in the top-left box, and it's straightforward to fill in the remaining 2's.



The 1 only has one possible place on row 2 now. That allows us to place the 1 in the bottom-middle box. The remaining 1's are easily placed.



The 4 has only one option on row 3. That fixes the 4 in the bottom-right box, and lets us fill in the rest of the 4's.



Many ways to fill in the 3's from here, and put a 7 into all the remaining boxes. This is the finished sudoku grid.

Green/red dots (stuck on this, probably a dead end)

Each box represents a number between 1 and 16. Reds are negative and greens are positive. This could indicate movement through the alphabet to form a message. (You can always reach any letter with a movement of either +1...+16 or -1...-16, assuming it wraps around on both sides.) I'm not getting any meaningful message as a result, though, so this might be a dead end...

Answer 3

(partial answer) First, the sudoku (the following is more like my solving process, so some steps may be out of order):

Each 3x3 box has 7 cells, so each box should have all numbers 1-7.

Step 1:

I filled the center with possible numbers
Then noticed that 6 can only go at the cells highlighted red in the respective box. This means R7C2 is the only place for 6 in that box.

Step 2:

Notice that R6C7 can't be 6 since the two possibilities of 6 in center box exclude this cell. So 6 can only go on the cells highlighted red on the right box. This means R1C7 is the only place for 6 in top right box.
Then we can fill the rest of the 6.

Step 3:

Top box can only have the red cells for 5. So R2C3 is the only place for 5 in that box. Which also gives us R1C6. And based on possibilities of 5 on bottom right box, we can also deduce R5C8 as 5. Then R8C4, R7C1, R4C2, and finally R9C9.

Step 4:

We can fill 2 in bottom right box now. Then R5C5. Then top left and top center boxes can only have 2 at R1 and R3. So top right box must have 2 at R2, which would be at R2C9. Then fill up the rest of the 2.

Step 5:

Left center box can only have R5 as 1. So R6C8 is 1, and we can fill up the rest of 1.

Step 6:

Top left and top center can only have R1 and R3 as 3. So top right must be R2C7. Then fill up the rest of the 3.

Step 7:

Then we can fill up the rest of the 4 and 7 easily. To arrive at this final sudoku part:

Now moving on to the red/green part. Since it seems like the formation of the dots have no meaning individually, let's replace it with the count for visualization.