Barry has already proven that he can run fast enough to open a time portal, and he can grab or carry people/large items while running.

In The Reverse-Flash Returns (S02E11), Barry and

The Reverse-Flash

need to open a time portal for Barry to throw him through.

Why do both of them run around in circles to build up speed instead of Barry just grabbing him at the end to throw him through the portal?

  • maybe the shock of being grabbed and accelerated to time-travel speed would have killed him?
    – KutuluMike
    Apr 29 '17 at 16:13

In the episode, it's stated that Flash and the other speedster must work together, adding Barry's speed to the other's, in order to open a time portal.

As you noted, Barry's been able to open time portals on his own before; however, as the earlier respondent stated, this was never something that he'd done on purpose (or, at least not until another few episodes, when he goes back in time to get Season 1 Harrison Wells to help him increase his speed).

So, it's not terribly clear why both their efforts were required to send the other speedster back through time.

A couple of possibilities:

  • They're basing their theory on what the other speedster has stated; that information may not be correct (whether by mistake, or by design).
  • The other speedster needed the additional speed to get the time portal open for some reason: he's just a little slower than Flash, or the distance he must traverse, or due to the presence of the Time Wraiths we learn of later.

NOTE: there's another questionable element here. It's not at all clear how the two speedsters, running at roughly the same rate, can have one push the other and thereby double his rate of speed. In the comics, speedsters have sometimes managed to use the Speed Force to temporarily give others super-speed. Perhaps that's what actually happened.


Barry, by himself, only has the ability to run into the past. He needs the help of another speedster to run into the future. In the show it is not explained why or how it works. It might be that he cannot create enough speed force to make a portal to the future.

In season 3 we see Barry run into the future, with the help of Wally.

Update: After rewatching the episode when Barry travels to the future. It is the force from the speed that Barry needs.

Wally: You sure this is going​ to work? Barry: I calculated the force from the explosion that propelled me into the future the last time. At your fastest speed, you can create 3 times the force. That's more than enough to get me to where I want to go.

The last time he went into the future was by accident. This was from him throwing the stone into the speed force creating the force to travel him to the future.

  • Do you have a quote or anything to back this up?
    – phantom42
    Jun 12 '17 at 16:52
  • I'll add some quotes after I re-watch that episode tonight.
    – Wesley
    Jun 12 '17 at 18:32
  • That is from season 3 episode 19
    – Wesley
    Jun 13 '17 at 2:00
  • Except barry has run back to the future by himself after having first run to the past.
    – phantom42
    Jun 13 '17 at 2:55
  • He runs back to the present. There must be a need for additional force to go past one's present time. In my opinion it doesn't make much sense but that is the way the show has played out so far.
    – Wesley
    Jun 13 '17 at 14:29

The times when Barry ran fast enough to go backwards in time was when he was running away from or trying to prevent a catastrophic event which would kill thousands of people.

Not only did he have to open a stable portal into the future, he also had to do so without being full of adrenaline.

There's also nothing to hint that he can do it on demand, but

Eobard Thawne

has a bit more experience with timetravel.

I also feel like The Flash grabbing onto him at such a high speed might cause him an injury like

a snapped neck.

  • I assume you meant to put those in spoiler markup, although I'm not sure about the last one; feel free to make further changes Jan 29 '16 at 22:10
  • @JasonBaker My bad, I looked up how to make spoiler blocks and apparently did it wrong Jan 29 '16 at 22:18

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