More on Thera

The name Thera appears to come from the Island that the Minoan civilization was living during the Bronze age when they were wiped out by a colossal volcanic eruption:

The island is the site of one of the largest volcanic eruptions in recorded history: theMinoan eruption (sometimes called the Thera eruption), which occurred some 3600 years ago at the height of the Minoan civilization. The eruption left a large caldera surrounded by volcanic ash deposits hundreds of metres deep and may have led indirectly to the collapse of the Minoan civilization on the island of Crete, 110 km (68 mi) to the south, through a gigantic tsunami. Another popular theory holds that the Thera eruption is the source of the legend of Atlantis.[4]

In EVE, could the Thera system and the other new hybrid low sec systems being added be the remnants of some old civilization related to the Sleepers, or the Sleepers themselves?

Welcome to Thera

From TheMittani.com:

Finally, CCP Mimic and CCP Fozzie had a chat before finishing off the stream. Fozzie is quite happy with how Phoebe has been received so far, particularly the features his team (Five-O) worked on, like bookmarks in space. They quickly pivoted to Rhea, however. Fozzie announced that CCP was adding more systems to New Eden with Rhea - a collection of new wormhole systems with unique mechanics and features. One system in particular he expects will be popular and notorious in the future: Thera, the first ever named wormhole system.
Thera is to be a hybrid wormhole system with unique mechanics combining aspects of wormhole, nullsec, and lowsec space. No capital ships or POS will be allowed or built within this system, but (unlike every other wormhole system) it will contain NPC stations and landmarks. Like wormholes, it will have no immediate player reveal via local chat, along with NPC Sleeper enemies. It is expected to have static connections to k-space as well as constantly changing non-static connections to both k-space and w-space. Players can live in Thera and have no idea where they'll be connected to tomorrow. Thera will be a major part of the overall lore surrounding the expansions beginning with Phoebe (involving Sleeper tech and so on).

CCP Rise has apparently described what he expects Thera will be as "the Mos Eisley of EVE" - the lawless hub of the universe, attractive to alliances on deployments, sightseers, and PvP-hungry pilots. A unique sun, multiple unique nebulae, new station colors, and other new graphics will add to the flair. Thera is expected to be available for testing on SiSi in two weeks, with an accompanying dev blog and forum post.
To summarize: Upon Rhea's release, there will no longer be grades of medical clone, nor SP loss on podkill. Players will also have access to Thera, a roaming Dark Mirror of Jita with unique features and mechanics. Those are two very big reveals, and they've certainly ignited the passion of the community in stream chat, #tweetfleet, and elsewhere. Expect more coverage of these features as information becomes available.

Awesome!