Archaebacteria is one of the three domains of life forms (Eubacteria and Eukarya) according to the three domain classification system of Carl Woese. It includes the primitive bacteria, which survive under extremely harsh environmental conditions (therefore also called extremophiles) such as hotsprings, hydrothermal vents, highly acidic and saline conditions.
As per the given information in the question, scientist were able to collect the organisms by dipping their microscope slides into the boiling hot springs.
A solar eclipse occurs when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. A solar eclipse can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface