On Saturday and Sunday the Hyde Park Art Center will host a symposium connected to its exhibit of ephemera from Sun Ra's sojourn in Chicago, where panelists will consider the cultural import of his work, but the odd hybrid lineup of the quartet put together to kick off the weekend says as much as any lecturer could about his influence on the world of music. Bassist Rollo Radford and drummer Avreeayl Ra, veterans of Sun Ra's Arkestra in one or more of its many incarnations, have worked in innumerable jazz ensembles both straight-ahead and avant-garde; keyboardist Jim Baker has played hundreds of free-improv gigs, as well as with acts as diverse as Freakwater, Nicholas Tremulis, and Ken Vandermark's Territory Band; and of course guitarist Thurston Moore is in Sonic Youth. This concert will be totally improvised, so don't expect to hear any tunes you recognize, not from Space Is the Place or Daydream Nation. But the rhythm section knows the Arkestra's peculiarly clunky big-band swing and blistering free-jazz broadsides, Baker's ARP synth echoes the grainy ray-gun tonalities of Ra's more interstellar moments, and Moore's harsh and hallucinatory feedback guitar, also heard in noise outfits like the Diskaholics, is sure to scatter sparks--the sounds of outer space are definitely within this group's grasp. My Barbarian opens and the Intergalactic Myth-Science DJs spin throughout, including during a screening of rarely seen silent footage of the Arkestra shot in France in 1970. a 9 PM, Hideout, 1354 W. Wabansia, 773-227-4433 or 866-468-3401, $20.