How would you separate fields with multiple spaces and store them in an array?

$ cat fieldone.txt
field1                    field2
------                    -------
this are numbers          12345
this letters              abc def ghi 

$ fieldone
this are numbers         
this letters             

#!/bin/bash

# NAME: fieldone
# PATH: $HOME/askubuntu/
# DESC: Answer for: https://askubuntu.com/questions/1194620/
# how-would-you-separate-fields-with-multiple-spaces-and-store-them-in-an-array

# DATE: December 8, 2019.

i=0                                     # Current 0-based array index number
while read line; do                     # Read all lines from input file
    ((LineNo++))                        # Current line number of input file
    [[ $LineNo -eq 1 ]] && continue     # "Field 1     Field 2" skip first line
    if [[ $LineNo -eq 2 ]] ; then       # Is this is line 2?
        # Grab the second column position explained in:
        # https://unix.stackexchange.com/questions/153339/
        # how-to-find-a-position-of-a-character-using-grep
        Len="$(grep -aob ' -' <<< "$line" | \grep -oE '[0-9]+')"
        continue                        # Loop back for first field
    fi

    field_one[$i]="${line:0:$Len}"      # Extract line position 0 for Len
    echo "${field_one[i]}"              # Display array index just added
    ((i++))                             # Increment for next array element

done < fieldone.txt                     # Input filename fed into read loop

field1         field2
------         ------
this is letter abcdef
this is number 123456