Michael Jordan turns 50 in a few days, as the cover of the new Sports Illustrated reminds us with supernaturally large numbers. Jordan’s greatness has proved non-transferable — his magic on a basketball court not rescuing him from failure as a team owner and executive — yet his mythic aura survives, even grows. The very fact that Michael turning 50 apparently rates as major news is funny, as if we’d assumed he alone might be impervious to the hands of time.

The implication is that when Jordan swivels that iconic bald dome of his and glances over his shoulder, he now sees the encroachment of mortality.

He should see something else gaining on him.

A 6-8, 260-pound freight train named LeBron James.

Caution: Objects In The Rear View Mirror Are Closer Than They Appear.

This isn’t to say, “Step aside, Michael.” (At least not quite yet.) This is to say that day is coming.

I know, I know. That day might not ever arrive by broad agreement. Legends are tough to penetrate once they harden into history. Michael is Michael, the untouchable. Not Wilt Chamberlain’s scoring prowess, Bill Russell’s rings or Kobe Bryant’s stardom could touch him. Not even the NBA-rescuing Magic or Bird could.

To many basketball fans (even some outside of Chicago), there will never be another Jordan in the same way there will never be another Beatles, or Sinatra. Why? Well, because that’s the way it’s always been, right?

Jerry Rice is the greatest receiver football has ever known by such acclaim that when Randy Moss said he thinks he’s better during Super Bowl Week it was met not with consideration but with incredulity. Moss had an argument but was drowned out by media cries of blasphemy.

Such is LeBron’s climb in the Jordan discussion, by perception, at least, still, but less and less by reality.

Heck, just Wednesday, former coach Stan Van Gundy said on 790 The Ticket he thinks LeBron is better than Michael was.

It certainly will continue to be arguable. But it isn’t blasphemy anymore.

Just this week — maybe the most remarkable week in a career full of them for James — he tweeted: “I’m not MJ, I’m LJ’’

He did that because he hears the talk, the comparisons, and he hears the volume increasing. He also did that because he is a student of the game, respects its history and understands Jordan’s unique place in it.

I found James’ five-word tweet interesting because essentially what it conveyed, at least to me, is, “We’re different.”

James will never match Jordan for scoring titles or likely for championships won, the two easiest, default barometers of basketball greatness.

It is in just about every other category that James is better. It is in the overall game that James is better, and it is that title of All-Around Greatest Player that LeBron has a chance to wrest from Jordan.

LeBron is closer in type to Magic Johnson, forward-big but as much a freak-sized point guard. Except Magic didn’t score like LeBron. Magic didn’t have the heft to muscle another team’s center on defense.

Miami coach Erik Spoelstra’s nickname for LeBron is “1 Through 5” because he can defend any position on the court. But he can play any position with the ball, too. LeBron could lead the NBA in scoring or in rebounds or in assists if it was his intention to do so. No other player is capable.