Date Timezone Oracle PLSQL

SQL>
SQL> -- TIME_ZONE to EST and repeat the previous query
SQL>
SQL> ALTER SESSION SET TIME_ZONE = 'EST';
Session altered.
SQL>
SQL> SELECT CURRENT_TIMESTAMP, LOCALTIMESTAMP, SYSTIMESTAMP FROM dual;
CURRENT_TIMESTAMP                                                           LOCALTIMESTAMP
--------------------------------------------------------------------------- ---------------------------------------------------------------------------
SYSTIMESTAMP
---------------------------------------------------------------------------
16-SEP-06 08.35.53.046000 PM EST                                            16-SEP-06 08.35.53.046000 PM
16-SEP-06 05.35.53.046000 PM -07:00
SQL>
SQL>
SQL>