answer:Behind every large scale financial endeavour, bei it the space programme, the large hardon collider, or sending a probe to an alien space portal to activate and open it, is a politician funding it. So the actual question is, would a politician task a scientist with opening it. And that depends on how it would affect his reelection chances, which in turn depends on how scared the populace is of any aliens that might be lurking beyond the veil. To speculate though, I would open it and send some probes through. The portal is there, so someone put it there at some point in the past, which means that whoever built the thing most likely knows that humans exist. If they have any plans of invading your planet, they will do that sooner or later, regardless of whether or not humans open the portal to have a peek. If they are hostile, then it is strategically wise to go through the portal, gather intel, and try to prepare for an invasion to the best of your ability. If you do not go, you will not know when they swarm out, how many there are, or what their level of technology is. If they are friendly, then there is no danger in establishing first contact and maybe get some advanced alien tech in negotiated trade agreements, which could solve all sorts of problems.