Lanterns are being released all throughout Midorea as part of the Novus Ekleipsis, an ancient ceremony performed when we enter a new Earth in the cycle. During the 10 days of the ceremony, all of Midorea will go dark due to the Solar Eclipse, as we light Lanterns to figuratively "drive out" the darkness that has been plaguing the world these past few years. It is up to you to collect the lanterns that have since burned out, relighting and releasing them back into the skies, brightening the darkness. Unlit Lanterns can be found by browsing the forums.
To release a lantern, go to your inventory and locate a lantern. Check the box and press "use", then follow the intructions on the next page to release the lantern. You'll earn Auras for each lantern you release, which can be spent in the Event Shop.
Once you have collected enough Auras, you can spend them in the Event Store on event items, which are only available during the 10 days this event is open. Once it ends, they will no longer be available.