saber si han pasado +12 hrs

[knzo25]

u.u

$timex= time("3000-m-d G-i-s");
$timey= time("Y-m-d G-i-s");
echo "$timex";
echo "<br>";
echo "$timey";
echo "<br>";
echo $timex - $timey;

pongo eso y me sale
1219096924
1219096924
0

PD: aora pruebo con
$timex= date("YmdGis");
$timey= date("YmdGis");
echo "$timex";
echo "<br>";
echo "$timey";
echo "<br>";
echo $timey - $timex;

parese que asi podre pues si le ago un if >= X.....
thx and cya

aaa!!!!!
no entiendo nada xD
(sigo sin entender porque no funciona XDD)

cya