Summary
The lightning network is a critical network upgrade that will allow Bitcoin to scale by orders of magnitude.
The lightning network is not a single protocol, but rather a collection of proposals and open source software that are designed to be synergistic.
Lightning network technology is already spreading to other cryptocurrencies, such as Ethereum under the name Plasma.
Many have claimed that Bitcoin and or blockchain cannot scale. There is some truth to this, but as we will see; scale is a moving target. There are many aspects to scaling and many approaches to "solve" the scaling problem. The Lightning Network is one such approach, which is also multifaceted. If the Lightning Network can deliver on the capabilities that its originators claim, then the argument that Bitcoin/blockchain cannot scale will have been dispelled (the theoretical speed is billions of transactions per day); at least for a while.
Interesting article about the lightning network from Hans Hauge over at Seeking Alpha.
Full link below
https://seekingalpha.com/article/4203403-bitcoin-scaling-exponentially-lightning-network