Liz Hostetler traces the origins of this Saturday’s March for Science back to Badlands National Park.

It was January and Hostetler, already no fan of President Donald Trump, had flown from Austin to the nation’s capital in January to attend the Women’s March. Around that time, the Badlands Twitter feed posted global climate statistics that seemed intended to contradict the president’s take on the issue, prompting the administration to order the tweets deleted.

Hostetler, and many others, saw the move as a dissing of science itself. She wondered if rumblings at the time about a science march would become action and, if so, who would organize a satellite march in Austin.

This Saturday, scientists and supporters of science from around the nation will indeed march on Washington. In Austin — at one of 16 satellite marches in Texasand 500 around the world — advocates for science will gather in front of the Capitol, with a "teach in" and rally, followed by a march to the Earth Day celebration at Huston-Tillotson University.

"I’m passionate about Austin, and I’m passionate about science," said Hostetler, a project manager at a software company who became a co-founder of the Austin march along with psychiatric nurse Krista Noland. "I’m hoping people will come away feeling that same passion."

At least 4,400 have signed up to attend the Austin march, and an additional 10,000 or so have indicated interest. Organizers say they aren’t sure how many will actually show up; between 1,000 and 2,000 people participated in a march calling for Trump to release his tax returns, according to the Texas Department of Public Safety, which was fewer than organizers expected. But the Austin Women’s March drew about 52,000, according to public safety agencies and independent crowd estimates— far more than organizers had expected.

Science advocates say broader concerns have come to a head with Trump’s election. Complaints range from proposed funding cuts to possible restrictions on foreign workers, to a general sense that the administration doesn’t value science. For instance, Trump chose a leader for the Environmental Protection Agency who is openly critical of its regulatory role, which the administration considers too burdensome.

Figuring out how the proposed cuts to science funding will affect Texas is difficult. No one has done an all-encompassing examination, but Rush Holt, the chief executive officer of the American Association for the Advancement of Science, said important members of Congress from both parties have made clear that "the president’s proposal (to cut science funding) is dead on arrival."

"As a former member of Congress myself, I feel confident that’s the case," said Holt, a Democrat who represented a New Jersey district from 1999 to 2015.

Holt and other national March for Science organizers are emphasizing their support for science, not criticism of others. Organizers have asked speakers to avoid personal or partisan attacks. They said the march isn’t about Trump, but a long-term trend of logic and evidence being displaced by ideology in the public square.

Yet organizers acknowledge the obvious: Trump is the catalyst of the march. And speakers might not keep their remarks within the organizers’ preferred bounds because, as march advocate and former EPA chief Christine Todd Whitman noted in a conference call, "These are people who don’t like being told what to do."

The overarching question that scientists have wrestled with for years is: Should they enter political debates?

How do they engage in public debate without being engulfed by it and losing the credibility they had cultivated by staying out of the fray?

"There is a risk," Holt said. "But I think there will be far more (gained) about the value of science, the relevance of science today, by speaking out. Is the better alternative to shut up, step back and turn your back on public problems?"

To Joe Hanson, one of the speakers at Saturday’s march in Austin, the answer is obvious.

"Science has intersected with politics since Galileo was setting up his telescope and getting into it with the Catholic Church," said Hanson, an Austin-based PBS science educator who holds a doctoral degree in biology. "Who funds a great deal of science in our world? It’s government," through NASA, the National Institutes of Health and other agencies.

Hanson said people’s views of the world are shaped mainly by personal experiences — which might have little daily contact with science as it’s practiced — and an adversarial approach often won’t work. He said his talk will focus on showing people that science has positively affected their lives.

"Almost nothing that lets us live the lives we live today are possible without science," from medicines that increase lifespans to iPhones that enable instantaneous international communication.

Noland, one of the co-organizers, has a particularly personal connection to science.

She created a Facebook organizing page for the march around the same time as Hostetler. They decided working together would serve the event better.

On the way home from the first planning meeting, Noland said, she was in a car crash "that literally crushed my face."

"If it weren’t for the science and technology and amazing physicians who saved my life and put my face back together, I wouldn’t be speaking today," she said. "I owe my life to science, as do we all, in some or another. Plus I’m part robot now, which is pretty cool."