php var_dump($object) or print_r($object) to a log file

This question is generic, and I would simply like to know how to dump objects to log files. In order to clarify things, i am elaborating through an example. I have been successfully using magento observers to call methods when certain events happen. As an example, I am observing for when a shipment is saved via : ``` <sales_order_shipment_save_after> ``` and i'm successfully calling a method. I would like to grab the shipment and simply dump the object to a log file. eg. ``` public function newShipment(Varien_Event_Observer $observer) { $shipment = $observer->getEvent()->getShipment(); $shipId = $shipment->getId(); Mage::log("shipment ({$shipId}) created/saved", null, 'shipments.log'); //trying to dump $shipment data into the log file Mage::log("({var_dump($shipment)}) ------", null, 'shipments.log'); Mage::log("----------------------------", null, 'shipments.log'); } ``` The shipment id is printed into the log file just fine, but obviously it does not dump the object the way i want it to as the code I have written is wrong. Can anyone tell me how I could dump an object to a log file and perhaps give me some advice on logging in general? thanks very much.