Ethereum is about to undergo a massive change.
The most-used blockchain, which powers the second-largest cryptocurrency by market value, is readying for a highly anticipated upgrade called the “merge.” It’s supposed to make it more eco-friendly and efficient, but there’s a lot of money at stake—it could push its cryptocurrency, Ether, to surpass Bitcoin in terms of market cap.
But there’s also a problem with a scary name: the “difficulty bomb.”
Here’s what the difficulty bomb is, how it connects with the merge, and why Ethereum developers haven’t delayed it.
Understanding the difficulty bomb requires understanding the merge.
Ethereum currently relies on proof of work, under which crypto miners must complete complex puzzles to validate transactions. This process requires a huge amount of computer power and is often criticized owing to its environmental impact. The merge would shift Ethereum to proof of stake, whereby users would be able to validate transactions according to how many coins they contribute, or stake, to the network. The difficulty bomb was created by Ethereum developers in 2016 with the merge in mind.
Once introduced, the bomb will exponentially increase the difficulty level of puzzles required for proof of work mining, ultimately making that mining impossible to do. This would lead to what Ethereum developers call an “Ice Age,” where Ethereum’s proof of work chain is forced to stop producing blocks, which validate transactions through mining, and “freeze.”
The purpose of the bomb is straightforward: Ethereum developers hope that the bomb incentivizes miners to accept the merge, pushing the adoption of the proof of stake chain further.
However, if the bomb arrives before the merge is ready to launch and without proof of stake in place, it could, well, explode.
‘It can get pretty dicey pretty quickly’
“The ‘risk’ here is that if we don’t delay the bomb quickly enough, block times will slow down on Ethereum. The block time starts slowing down by very little, but then every two weeks, the slowdown doubles,” Ethereum developer Tim Beiko told Fortune.
If the bomb goes off while developers are still testing the merge, they’d need to work extremely quickly to diffuse it. But Beiko told Fortune that developers could delay the bomb in roughly four weeks’ time, saying that the process isn’t difficult.
Even still, “the concern with taking this see-as-we-go approach is that it can get pretty dicey pretty quickly for devs once the bomb is activated,” Christine Kim, research associate at investment firm Galaxy Digital, tweeted about an Ethereum core developer call on Friday where the bomb was discussed.
Despite concerns, developers decided not to push off the bomb, citing a few reasons.
To Beiko, the process for delaying the bomb would “create more work for developers, so given the huge desire from everyone to see the merge happen as soon as possible, if we can save a few weeks by not delaying the bomb, that might be worth it,” he told Fortune.
Even Ethereum cofounder Vitalik Buterin stepped in to support keeping the bomb as is: “We have to evaluate the pain of doing an extra delay versus the pain of living with 21- or 25-second blocks for a while, which is something we have done before, and the world didn’t end,” Buterin said on the call.
Not everyone was sold on developers’ explanations for holding off on delaying the bomb.
“I personally don’t think this is a strong argument for keeping the bomb schedule as is,” Kim tweeted. “It’s undue stress [in my opinion] on devs but the bigger reason I think devs have held off on agreeing about a bomb delay today is optics.”
For example, in a hypothetical situation, if developers pushed the bomb off to December, it would give them a good amount of time to work on the merge, conduct tests, and coordinate action, Kim said, but “optics wise, [it] looks bad, which shouldn’t matter but in reality, it does.”
“As much as devs know the merge will happen when it happens, they probs don’t want to be bombarded with more criticism, hysteria, and just incorrect media saying the merge won’t happen or will happen in December just cuz the bomb got pushed back to then,” Kim said.
As of now, developers are continuing to test the merge. After their most recent tests, they found a multitude of issues that would need to be solved before the upgrade takes place.
“Having a client crash or hit a weird bug late into the process isn’t ‘delaying the merge,’” Beiko said, “it’s making sure that Ethereum doesn’t go down during the upgrade, which is the core thing we are all trying to achieve.”
