You knew it was coming, but today, it finally begins. Second-quarter earnings season is upon us, and there's a lot at stake as analysts look to company results to see if fears about a slowdown for the U.S. economy actually come to pass. Based on today's stock market performance, investors seem nervous, as some poor data on Japanese machinery orders and Chinese inflation support the recessionary case. As of 10:45 a.m. EDT, the Dow Jones Industrials (INDEX: ^DJI) were down about 55 points.

As is traditional, Alcoa (NYSE: AA) will lead things off with its Q2 earnings report after the market close. Estimates have the company posting a much smaller profit from last year's second quarter. As Fool analyst Brenton Flynn noted earlier today, low prices for aluminum overall have hurt the company, although strong demand for specialized aluminum-fabricated products has helped hold Alcoa up. The stock is down about 0.7% this morning.

Merck (NYSE: MRK) climbed to another multiyear high this morning, rising 1% to reach levels it last saw before the financial crisis. In general, many investors saw the Supreme Court ruling on health care as positive for Merck and its big pharma peers, as more people insured would mean more potential prescription drug demand. We'll have to wait until July 27 to find out how Merck is doing, although analysts expect modest growth compared to last year.

Finally, Boeing (NYSE: BA) is up three-quarters of a percent on a good day for the aerospace and defense industry. The company got a $7.2 billion order for 75 of its 737-Max airplanes from aircraft-leasing company Air Lease (NYSE: AL). As Bombardier celebrates an agreement to sell 15 jets in a $1 billion contract with an unnamed buyer and Raytheon scores a $636 million missile defense system contract, it's possible that the industry has finally hit bottom, as long as economic growth supports the airline business and future defense budget cuts don't prove more extreme than currently expected.

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