Temp tablespace issue.

This is curious
SQL> l
 1  select tablespace_name, file_id, bytes_used, bytes_free
 2* from v$temp_space_header
SQL> /

TABLESPACE_NAME              FILE_ID BYTES_USED BYTES_FREE
------------------------- ---------- ---------- ----------
TEMP                               5    1048576 5367660544
TEMP                               1 5242880000          0
TEMP                               2 1048576000          0
TEMP                               3 5242880000          0
TEMP                               4 5242880000          0

SQL> SELECT * FROM dba_temp_free_space;

TABLESPACE_NAME           TABLESPACE_SIZE ALLOCATED_SPACE FREE_SPACE
TEMP                              22145925120  16778264576              22131507200

so the select from v$temp_space_header tells me there is 5GB free and the select from dba_temp_free_space tells me there is 21GB free.

Which one is right ?

Database 11.1.0.7 on HP UX itanium.