A Super-Hearing Aid
But did you know that Superman can also hear fast?
"That's absurd," you say. "You can't hear fast anymore than you can see fast or smell fast." Well, at least two of the architects of the new DCU order disagree with you.
One is Geoff Johns. Back in November's JSA #67, there is a scene with Power Girl standing before Sue Dibny's grave. In one panel, she lays a rose at the tombstone. In the next panel, she begins to cry, and in the third, there is a hand on her shoulder and an off-panel voice saying "Hi."
The hand and the voice belong to Superman. He says he was in New York and heard her crying, so he came to check on her. PG replies "That's almost six hundred miles away." (I don't know where the cemetery is supposed to be, but to illustrate, that's about the same distance between NYC and Columbia, South Carolina.)
The speed of sound at sea level is about 761 mph. Thus, the sound of Karen's cries should have taken about 47 minutes to reach Superman's ears (and we'll just put aside the question of Clark being able to single out the sobs of an occasional acquaintance from several states away).
But Superman has super-fast hearing, so sound waves move faster toward his ears. He responded to PG's tears within the timeframe of a single panel, though of course, we don't know how much time elapsed between those panels. Presumably not very long at all. Let's be very generous and say two minutes: one minute for the sound of her crying to miraculously reach Clark's ears, and another minute for him to make the trip. Six hundred miles in one minute equals 36,000 mph, or somewhere in the vicinity of Mach 50. He clearly wastes no time when it comes to consoling friends.
But we can't blame Johns for creating super-fast hearing, because that is peanuts compared to what showed up three months earlier, courtesy of Greg Rucka in Adventures of Superman #631. Near the issue's end, Clark hears a sniper's bullet being fired at Lois, who is covering the war in the middle-eastern nation of Umec. He immediately flies to Umec, and catches Lois as she falls to the ground, hit by the sniper's bullet.
I'm hardly the first person to be skeptical of this action.
Where is Umec located? Heck if I know. I love DC's fictional geography, but they tend to be pretty vague on actual borders. So I'll be conservative and use Jerusalem (which is about as far west in the Middle East as you can get) as a marker. And the distance between New York and Jerusalem is about 5700 miles.
Lessee...5700 miles at 761 mph...the sound of that bullet would've taken seven and a half hours to reach a normal person's ears. But not Superman's. He hears that bullet instantly, manages to distinguish it from all the other sounds from places closer than Umec (including, but not limited to, Europe and both Americas), and recognizes *that* bullet as the one bullet in a warzone he must immediately respond to.
The Earth's circumference is about 24,900 miles. According to Rucka, Supes' not only is capable of hearing any sound made over half the Earth, but he also hears it all instantly. Such marvelous ears, those Kryptonians have.
AoS #632 gives the elapsed time between gunshot and Superman's catch of Lois as 3.712 seconds. And just for convenience's sake, we'll even grant Clark insta-hearing for the sake of this calcuation. 5700 miles in 3.712 seconds? Superman was clocking in at just over five and a half million miles per hour.
Your mileage may vary on Superman's flight speed, though I think the latter is really pushing it. (To be fair, though, he's been known to move even faster, though usually not in the atmosphere. The end of the first Superman movie, for instance.) But as for superspeed-hearing, I'd rather see that get the same fate as Superman's once-used (and thankfully forgotten) power of invisibility.