On the notion of time travel

A friend of mine who is an accomplished astrophysicist recently advised in a private e-mail that the Higgs Bozon, the elusive subatomic particle wich travels slightly faster than the speed of light has been positively identified, and his fellow scientists at the CERN supercollider are conducting follow-through experiments to re-confirm their data before making the "big announcement". Some of his fellow frontiersmen, cutting edge visionaries like Michio Kaku ad Brian Greene are suggesting that this discovery may lead to the possibility of "time travel". Of course they are referring, at least initially, to clinical experiments on the subatomic level, but for us lay-people in the post-Star Trek era our minds are now just a bit freer to wander the Wellsian galaxy's newest dimension and dream of a "time" when whole people may be able to leap ahead and see what the future holds , or to travel back to rectify the past.
This brings to mind a question; if you could travel back in time and re-arrange history what would be, say, your top 5 objectives?. Would you, for instance, try to advise physicians in the 14th century on how to prevent the spread of "the plague"? Would you intervene in Salem to rescue the victims of the infamous witch trials? Would you try to distract Martin Luther King Jr. on that fateful day in Memphis to spare him from te assassin's bullet? Would you rescue Jean D'arc, or urge Galileo to hold his ground, or convince Einstein to denounce nuclear weapons from the start?
Of course we would all have personal objectives as well ; the youthful lover you wish you have been more attentive to, a wrong answer on a test or the contest you were oh, so close to winning, or a relative or friend you wish you and spent more time with, etc. In the Aladdin's Lamp scenario my first wish is always for world peace or the restoration of environmental health, but the third one is always personal, like for all of my family and friends to be prosperous and happy and to live active lives till the age of 120 or so. But while I enjoy fantasy fiction as much as the next person my overbearing sense of pragmatism always kicks in and, frankly, I am prevented from imagining that time travel would be a good thing, at least for the foreseeable future.
Consider that we have already reached a point where space travel is available for private individuals and is no longer the sole purvue of governments and their sanctioned agencies, yet it remains far beyond the means of all but the obscenely rich. Even if the economy of scale were to lower the costs of orbital travel enough to allow people of average means to take a spin, the world's majority would still be excluded. Similarly, if time travel were to become possible, and then to become accessible to individuals not bound by the strictest of scientific protocols, who would be the first to likely go? Wouldn't it be the Rockefellers, the Saudi princes, the Koch brothers, or the Donald Trumps of the world? Judging by their preset actions could we trust them to be our beneficent emissaries to the past? Or would they conspire to create conditions that might facilitate their further concentration of power? What measures might they take to pre-defeat their competitors? Would they try to undo past atrocities, or simply commit greater ones? Hasn't history abundantly and conclusively shown that disproportionate concentration of power is simply incompatible with humane and egalitarian values?
Fortunately backward travel is still only the stuff of fiction. Particles traveling faster than light move forward in time, ot back. The only past we can ever expect to influence is the
one we are creating in the present and it is here, in this time that wealth and power are being concentrated on a scale never before witnessed.
Empires rise and fall and always at a tremendous cost to humanity and the planet. Today we preside over one of the largest extinctions in the earth's discernible history, caused, i no small part by the alarming proliferation of toxic compounds and wholesale degradation of the ecosystem due to deforestation, mining, urban sprawl, reckless transportation of exotic species, and the industrialized world's addictions to fossil fuels and beef. The tenuous survival of many species, like the Bengal tiger, the Lowland Gorilla, the North America Grey Wolf, Whales, or the Appalachian Hemlock are now completely dependent upon continuous human intervention, and, therefore, the continuation of government programs which provide for their protection. The noblest of our scientists today, like professor Kaku, or my friend whose e-mail inspired this reflection lend their voices to the struggle for justice, both social and environmental, and even if we could send them back in time I would still hesitate, for they are so badly needed in the present, as are all of us if we hope for a future worth realizing and are willing to do what is necessary to make it real.