The account posted 10 tweets total about the hearing, including a link to a video feed of the testimony. It shared sound bites from each of the panel’s other three witnesses: Harrison Schmitt, an Apollo 17 astronaut and former U.S. senator from New Mexico; Lt. Gen. Thomas Stafford, an astronaut on Apollo 10 and two Gemini missions; and A. Thomas Young, who was the mission director for the Viking Mars program and a former director of Goddard Space Flight Center in Greenbelt, Maryland.

“There must be a permanent public and political commitment to deep-space exploration and development,” the account quoted Schmitt saying.

"There must be a permanent public & political commitment to deep space exploration & development"- Hon. Harrison Schmitt — Sci,Space,&Tech Cmte (@HouseScience) February 16, 2017

It also quoted Representative Lamar Smith of Texas, the committee’s chair, and Representative Brian Babin of Texas, whose district includes NASA’s Johnson Space Center, talking about American leadership in space. If you’d read that feed for coverage of the two-and-a-half-hour hearing, you’d be forgiven for thinking Stofan didn’t show up at all.

But she testified at length. She gave detailed answers to numerous questions about the space agency’s Earth science mission, about NASA’s Mars trajectory, about human space exploration, and plenty of other topics, many of intense public interest. It was curious that she didn’t appear at all in the committee’s Twitter feed.

I called the committee’s offices to ask about this omission. The person who answered the phone Friday paused and said, “that’s a good question,” before referring me to the communications staff. At the time of publication, I had not heard back.

Stofan was nonplussed, both on Twitter and on the phone from her vacation home in North Carolina last weekend.

“I understand that it’s probably mostly because they are the Republican witnesses. I was invited by the minority party, the Democrats. But the optics of being the only woman…,” she trailed off, with a rueful laugh. “You know, I understand, that’s the way the system works. I hope we’re turning away from that system.”

Stofan was referring to the systemic mistreatment of women in science, as supported by a wealth of scientific papers in academic journals, which speak to the persistence of sexism, ossified gender roles, the prevalence and endurance of bias, and the underrepresentation of women (especially women of color). This body of research demonstrates the detrimental effect of these biases on Ph.D.s, salaries and careers and the importance of representatives and role models.

For these reasons and others, Stofan’s omission prompted an outcry. “Don’t ask questions about encouraging young people to get into STEM and then make it look like it's only for old white guys,” one woman wrote to Stofan. “As a woman seeking a STEM career, for that matter a human who cares about science ... this bewilders me,” said another.