I noticed this hole when I got to work in the morning. It lets out enough air that I can hear it when I try to inflate the tire. What are my options here, aside from buying and mounting a new tire? Is this fixable with liquid sealant? A rubber rope kit?

I'm not taking this bike past 90mph, so any fix doesn't need to be capable of withstanding incredibly high stress. But I don't want to be unsafe, either. Thanks for the help.