Classes not working in Functions!

Guys, what am I missing?

I am writing a plugin, that includes something like: class.php

In class:
class random_class {

function unique_activate_function() {
error_log(“this worked”)
}

}

my main file:

$object = new random_class;

$object->unique_activate_function(); //works perfect!

register_activation_hook(__FILE__, ‘activate_random_plugin’);

function activate_random_plugin() {
global $object
$object->unique_activate_function(); //FAILS
}