As the Balrog flies

[Morwen]

Originally posted by Farael

At that time, Morgoth was still very much a "spiritual" being, he was not yet confined to his earthly form, therefore I'd speculate that "punches and stabs" wouldn't do much damage to him.

I don't have my books handy, but I believe that Ungoliant fought Morgoth with the darkness she could spew and so I'd speculate that the battle was more of a spiritual struggle than a physical one. Of course, the spiritual struggling might have had physical expressions (such as darkness and light, or perhaps cold and fire) yet this fight might have raged on for a long time on planes other than the physical one until the Balrogs finally came to the rescue.

The way it is described in the Silmarillion I didn't think that Morgoth was putting up much of a fight, either physical or spiritual. Ungoliant had "grown great, and he less by the power that had gone out of him" and so her "cloud closed about him, and she enmeshed him in a web of clinging thongs to strangle him" (Silmarillion, Of the Flight of the Noldor). My impression was that Morgoth, weakened, was overcome and couldn't fight back, only struggle against the darkness that Ungoliant spewed forth and the physical constraints of her webs and that if he had to be rescued, his rescuers needed to show up quickly. At this point he lets out his 'terrible cry' which summons the Balrogs.

Originally posted by Farael
So perhaps, at the time of Morgoth's fight with Ungoliant, balrogs were still able to become wholly spiritual and as such they might have been able to travel great distances at amazing speeds.

I agree. When Arien, spirit of fire, undertakes the guidance of the vessel of the Sun it is said that she abandoned her physical form and thereafter was "as a naked flame, terrible in the fullness of her splendour" (Silmarillion, Of the Sun and Moon). The Balrogs are described as coming to Lammoth "as a tempest of fire" which suggested to me that they had journeyed in spirit form.

[Formendacil]

One point about Morgoth and his physical form...

Originally Posted by Of the Darkening of Valinor

Now Melkor came to Avathar and sought her out; and he put on again the form that he had worn as the tyrant of Utumno: a dark Lord, tall and terrible. In that form he remained ever after.

Now, I will grant this this does not necessitate that it was right then that Melkor was last about to change his form. It simply means that was the last time that he did so. Though there is no documentary evidence to back it up, I would take the statement that "much power had gone out from Morgoth" as an indication that he was, in fact, unable to change his form again.

[The Sixth Wizard]

The Sil says that the "Bridge of Menegroth was but 50 leagues distant from the gate of Angband. This is 277.8 kilometres or about 172.5 miles. I'd say that judging by the map of Beleriand that Lammoth is about the same distance away. According to this essay your height x .415 equals your striding length. Sure, Balrogs are probably different, but maybe that can give us an idea. How tall were Balrogs? Eight, nine feet? More?

If nine feet that means their stride length was 3.735 feet and 1.14 metres. If they stepped once a second (they're kind of hulking) then they would get there in 243,684 seconds or

(drumroll please)

Sixty Seven Hours!

...Okay that was useless.

[Elmo]

They have all those mountains to climb aswell...

[The Sixth Wizard]

True. But then they could just slide down the other end, couldn't they?

[Morsul the Dark]

well think about it, they were summoned by his scream sooo they weren't far away(I don't care what a map says) Sounds travels at 540feet per second about 170 meters a second(About) so if they instantly heard him then they were about...right there

[Inziladun]

I'd put forward the scream need not be only a physically heard sound, but a psychic cry as well. Angelic spirits who had pledged their devotion to Morgoth could have been capable of some sort of spiritual connexion with him.
The Silm makes it quite clear the Balrogs were responding to Morgoth's call from Angband, so travel in some sort of spirit form seems the logical explanation.