How do I extract the last name from each cell in a name column and assign it to name array?

I think i've got a good start, but I'm having a tough time taking this to the finish line. Could someone help me out?

I have a name column(G) in my spreadsheet. I want to pull the only the last name out of each cell and assign it to an array called name_array.

I know that my If function is working because if I set each name_cell to the LastName variable it substitutes only the lastname in each cell of the column, but I cannot figure out how to assign that to the array.

Here is my code thus far. Can someone please help me out and point out what I'm missing?

Sub create_namear()

Dim name_array() As Variant
Dim name_range As Range
Dim name_cell As Range
Dim n As Long
Set name_range = ActiveSheet.Range("G2:G" & Range("G" & Rows.Count).End(xlUp).Row)
ReDim name_array(name_range.Cells.Count)

For Each name_cell In name_range.Cells
    Dim Lastname As String
            If InStr(name_cell, " ") > 0 Then
            Lastname = Split(name_cell, " ")(1)
            End If
    name_array(n) = lastname.value
    n = n + 1
Next name_cell

Debug.Print name_array(1)

End Sub

Name Column