On Friday, President Donald Trump signed an executive order effectively banning entry to the United States for citizens from certain Muslim-majority countries. The ban could have massive ramifications for science, and scientists — like computational biologist Samira Asgari, for example, who was stopped from boarding a flight in Frankfurt on Saturday morning. She was heading to Boston, and her new job at Harvard Medical School.

The ban could have massive ramifications for science and scientists

The executive order that Trump signed Friday night is ostensibly to “protect the American people from terrorist attacks by foreign nationals” from Iran, Iraq, Libya, Somalia, Syria, Sudan, and Yemen. Already, people traveling from these countries have been stopped from getting on US-bound flights. Some were detained at airports until a federal court ruled that their detainment was unlawful.

Trump’s “Muslim ban” also prevents refugees from seeking safety in the US for at least the next four months — and indefinitely, if they’re from Syria. It bars non-citizen, but legal US residents from returning home. And, as Asgari found, it also blocks scientists from contributing their highly trained labor and expertise to American scientific institutions. Thousands of scientists and academics in non-science fields have pushed back against the travel restriction, signing a petition that urged President Trump to reconsider the order.

I was pretty excited to join @soumya_boston's lab but denied boarding due to my Iranian nationality. Feeling safer? — Samira Asgari (@samsam_86) January 28, 2017

Asgari, an Iranian national, had recently finished her PhD at the École polytechnique fédérale de Lausanne in Switzerland. She was on a layover in Frankfurt on a flight from Geneva to Boston when she was pulled out of the boarding line.

The man who took her aside told her he was a government official, and that she would not be allowed to enter the US for another 120 days. She told him that by then, her visa will have have expired. But it didn’t matter. (He also may have been mistaken, too — right now, the ban appears to be 90 days for citizens of the listed countries.)

“Feeling safer?”

Asgari was not refunded the cost of her ticket from Frankfurt to the US, but was issued a free return ticket to Geneva. So back she went — with nowhere to live after Sunday, no job for her or her boyfriend, who had quit his job to go with her and support her scientific career. And no certainty about the future she had been working toward.

“I was very shocked that all my efforts, that all I’ve done, can be undone — just like that,” Asgari told The Verge. (You can read a Q&A with Asgari on Vox.com.)

Asgari had just spent the better part of a year applying for postdoctoral research jobs, interviewing, and applying for funding. The reputation of US academic institutions drew her to Boston. “I always knew that in my field, Boston is one of the greatest places in the world to go, if not the best,” Asgari says. “So, I always knew that I want to do a postdoc there.”

“All I’ve done can be undone — just like that.”

She secured a position as a postdoctoral scientist in Soumya Raychaudhuri’s lab at Harvard Medical School, where she planned to investigate the genetics and genomics of tuberculosis. In the fall of 2016, she was also awarded a fellowship from the Swiss National Science foundation to help fund her work.

Her research could have direct benefits here in the US, where millions of people have latent tuberculosis infections. Latent TB can, in some cases, go on to cause life-threatening and contagious disease. But now, with her ability to travel to the US up in the air, Asgari might have to take her expertise and research funding to another country.

“My resources are me, basically. What I've studied, what I've done. And that cannot be taken away from me,” she says. “I know that there are other places in the world that do very good research as well. I can go elsewhere.” She worries about other people who are not at a stage where they can be as flexible. For example, researchers who are working in the US, but left to go to a conference or visit family abroad — and who now can’t return to their jobs, homes, and loved ones.

“My resources are me, basically. What I've studied, what I've done. And that cannot be taken away from me.”

Raychaudhuri, the Harvard professor who hired Asgari, says that he’s hopeful the government might alter its position and that he, and Harvard, will be able to bring her to the states. “I think that we're in a wait and see mode, at least until Monday,” he says. “She may obviously have to consider other options for herself — and if she does that, we would fully support her.”

If the ban continues, Asgari could be one of the first drops in a scientific brain drain from the US. That’s because this executive order shows that the government is willing to abruptly curtail the rights of non-citizens legally allowed to be here. The prospect of suddenly being locked out of the country without warning or recourse might make it very difficult to convince foreign nationals to lend their expertise to American innovation.

“I can go elsewhere.”

Raychaudhuri estimates that half of the people working in his lab are visa holders — although none are from the seven listed countries. “But obviously it makes you feel a little bit nervous — not just for [Asgari], but for everybody else and what this means for visa holders going forward.”

The travel ban could also mute scientific dialogue. After all, who would want to hold international scientific conferences in a country where entire nations are banned from participating?

That’s why, as of early Sunday morning, nearly 5,000 professors appear to have signed a petition requesting that President Trump reconsider the ban. The petition calls Trump’s executive order discriminatory, harmful to American interests, and “inhumane, ineffective, and un-American.” By Sunday afternoon, the number of signatures had climbed to more than 7,000.

While the organizers of the open letter have not identified themselves, they told The Verge that they only include signatures sent from email addresses ending in ‘.edu’ — which signifies the email came from someone at an academic institution. Between 40 and 50 volunteers are working to verify those addresses. While The Verge has not checked all the signatures, four of the half dozen signatories The Verge contacted replied, and said that they had signed the petition — and confirmed another signatory, as well.

The order is “inhumane, ineffective, and un-American”

One of the confirmed signatures was from Andrew Fire, who shared the Nobel Prize in Physiology or Medicine in 2006. He told The Verge in an email that the policy will not make America safer. “Shutting [people] out after the extensive and careful vetting that has already occurred would be an act of pure cowardice on the part of our nation,” he says. “Sending asylum-seekers back to the repressive regimes who are seeking their harm would be a crime.”

Rodolfo Dirzo said that he worries that “this madness has the potential to escalate to many other countries of the world.” Chaitan Khosla, a Stanford chemistry professor, called Trump’s executive order a particularly worrisome example of “the xenophobia that is spreading like the plague in our country.” He added that he’s certain that the order will hurt science, but he’s also afraid of its broader, toxic effects. “Our country is becoming unrecognizable to me,” he says.

“I think everybody will eventually suffer the consequences of these decisions,” Asgari says. “Some sooner than the others, and some more than the others — but science is for sure going to suffer.”

Update 6:10PM ET, 1/29: Updated to include new information about the signature vetting process for the open letter “Academics against immigration executive order.”

Donald Trump's executive order, explained