Do you think scientists have an ethical obligation to speak out when a problem seems so severe

Yes, when a problem is severe or harmful, scientists are ethically and legally obliged to speak out.

Scientific experiments and testing are vital processes that lead to innovations, medicines, procedures, etc., that better human life. While scientific testing is required before a medicine, product or procedure can implemented or introduced in the market, it is essential to stop or prevent further testing when a severe problem or harm arises at the experimental stage.

For instance, if a clinical experiment testing the effects of a new hair loss prevention drug finds that consumption of said drug causes severe nausea and dehydration, scientists must speak out or stop the experiment  to prevent further harm. A failure to prevent harm is both highly unethical and liable to legal consequences.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.