Looking for some constructive criticism as I learn HTML & CSS. I did this table exercise and it was a bit challenging at times. I still do not quite understand the rowspan. For example, “Jovian planets” takes up a space of 8 even though it visually only covers 4 rows of space? Also, wasn’t sure if I put the correct content in body. When it says headers I figured anything with “th” should be outside of the tbody but it did not quite work out like that. so I did what I could do. Any positive input is welcome. Thanks LINK TO CODEPEN BELOW
Hi @ArthurAsam and welcome to the community 
There are quite some errors showing when pasting your code into the W3C HTML Validator. I recommend working through those and reporting back when you have solved them or need assistance in understanding the explanations.
A few hints:
- The “
<caption>” error is about the location of the element. - The “exceeded the column count” errors have to do with the definition inside
<colgroup>. - The “stray end tag” errors are caused by the nesting of
<tr>s. There should only be one per table row.
I hope that gets you further. I’m happy to have a second look when you’re ready. 
Happy New Year,
Michael