I just bought a horse at Whiterun and was traveling North East on an assignment when I saw some Nirnroot by a stream. The moment I dismounted to harvest it, my horse and I were pulled into a hyperspace tunnel. As the world around us distorted, I saw the Nirnroot streak away in front of me while rocks and trees stretched to a vast width. After a split second of being hyper-thrust backward 300 feet, I was suddenly standing along side the Nirnroot... with my horse nowhere in sight. Nowhere.

The Wiki says this is an http://elderscrolls.wikia.com/wiki/Horse_%28Skyrim%29. But where is my horse? Days have past and it has not returned to the Whiterun stables. I can't find it waiting for me anywhere near the incident.

Has this happened to anyone else? Is there a console command I can use to get the horse back? That's not cheating, since it was taken from me by a bug. Thanks.

I read through that link you provided; interesting stuff.
No mention of 'hyperspace tunnels' though...
But I've sure never seen that (in 1000 hours of playing).
Too weird...!

Sounds like someone's been hitting the skooma...

"Scotty? What is that damn horse doing standing in your transporter? Get rid of it- it's getting poop all over the place!"

"Aye, Cap'n! Dunno where that came from..."

try loading an earlier save.
or just fast travel to a different area, and see if your horse shows up.
if not, try step one.

I lost two horses. One vanished after I got off to fight a necromancer and I thought the second one had been killed by a dragon, but I couldn't find its body. Last night I walked out of Riften,and they were both there waiting for me. So, check all the stables, maybe it is at one of them.

My grandfather had a pony when he was young that apparently used to sneak into his bedroom of the second floor of their house. Actually happened. How does a pony SNEAK anywhere, let alone around a house at night, upstairs? Answer? Hyperspace tunnel available only to equine races.

Ha! That's awesome!

What about lockpicking? When I was little I had a really shrewd Shetland pony called Peanuts. She used to buck me off a lot, and it turned out that she was getting into the food for the race horses. She would open the locked forage room door by turning the key with her top lip. True story.

Lockpick level 100. Sneak level 100. Next thing you know it'll be picking the ferrier's pockets.

My horse finally returned to Whiterun stables. As a previous poster said, it returned after I fast traveled (using the carriage, since I didn't want to walk... that's why I bought a horse).

After the hyperspace incident, my horse charges into battle with me, never leaving my side. When attacked by some skeletons and a necromancer, a rode the horse safely past them before dismounting. Pitty the skeleton who hit the horse with an arrow, because the horse came charging in and stomped it, then started stomping the necromancer.

Two-handed level 100. Steel Hooves of Fortify Two-Handed.

Glad your horse came back, and came back fortified as well.
Spose both of you have left any questions or explanations regarding 'hyperspace tunnels' unsaid? Might be for the best.

The hyperspace tunnel also happened to me when I got off a horse I borrowed from an Imperial fort. Every place was safe to get off except Blackwater Crossing. Really weird.