This month’s announcement from Party City that it’s closing more than 40 stores as it grapples with new challenges, including diminishing helium supplies, likely came as unwelcome news to customers who count on the store for their balloon and event planning needs. But for scientists like Mark Elsesser, the announcement was something of a relief, inflating hopes that the public, and the government, might start paying closer attention. “When it comes to helium, we’re at a tipping point,” said Elsesser, who is the associate director of government affairs at the American Physical Society, a nonprofit association of physicists. “Party City...