From my home on the west bank of the Columbia River in Richland, Washington (46.3°N latitude), I have an unobstructed view of the sunrise along the east bank during an entire year. As a retirement project after a career of teaching and research in physics, I decided to take photographs of the sunrise for a year and, and at the same time, carry out…

The camera obscura is a well-known optical device in the form of a closed box with a hole in one of its walls through which light rays pass, forming an inverted image of the external objects on the opposite wall, as can be seen in Fig. 1(a). Despite the simplicity of its basic design, they have been widely used by scientists and artists. In…

We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the…

Physics teachers are sometimes asked to teach an astronomy course for non-majors. One can't make that class dance and sing without the starry night, but on a brightly lit campus viewing deep sky objects may seem impossible. Hence instructors often opt for planetarium shows. However: 1) Planetariums aren't the real thing. 2) People living in large…

The Sun does not return to the same position in the sky every 24 hours. At local noon, for example, the Sun will appear higher in the sky as we move from winter to summer solstice. In addition, and perhaps more surprisingly, solar days (the roughly 24 hours between subsequent local noons) vary in length, causing the Sun to be east or west of its…

Even though many physics teachers take their students on a calculation adventure through circular motion and Newton's universal law of gravity to determine Earth's velocity, most of us leave it at that. We present the final result and say, "Look, Earth is moving around the Sun at about 107,000 km/hr (66,000 mph), yet we can't feel the motion…

Laboratory astrophysics and astrochemistry are emerging fields highlighting the importance of laboratory simulations and experiments to benefit remote observations. In particular, ice mixtures found in the outer solar system may offer insight into the early evolution of organic molecules. H[subscript 2]O-ice mixtures containing other species such…

The Double Asteroid Redirection Test (DART) is a National Aeronautics and Space Administration--European Space Agency collaborative mission to test the feasibility of defending Earth from a catastrophic asteroid impact by using a spacecraft to deflect the asteroid away from the planet. Launched on Nov. 23, 2021, the DART spacecraft will intercept…

A solar eclipse provides a well-characterized reduction in solar radiation. Solar radiation is a driving factor in meteorological and climate models. Hence, solar eclipses provide a unique opportunity to do large-scale meteorological experiments by measuring the effects on temperature, pressure, and wind while the atmospheric conditions stay…

The concept of redshift is very often used in teaching physics and astronomy, as well as in science public outreach. Redshift is an interesting topic, used to describe many physical processes such as the Doppler effect or the expansion of the universe. Nevertheless, there are unfortunately also misconceptions about redshift. When facing the…

The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere.…

The acceleration of gravity in Earth's interior is determined by the density distribution in Earth. A remarkable result is that the acceleration is approximately constant all over the mantle, which amounts to about 84% of Earth's volume. This result can be explained by a simple two-layer model of Earth, showing that the constancy of the…

In the last decades spectroscopy began to play an essential role in physics education research with the recognition that atomic spectra constitute a good occasion to study the concepts of quantum mechanics. Moreover, activities in which atomic spectra are studied in order to understand star structure and evolution have proved particularly engaging…

The theory of the Big Bang is accepted nearly universally among the scientific community. However, there is a small cadre of individuals who dispute this consensus and they point to a handful of datums that don't fit into the picture. One such datum is the existence of a star with an age reported to be older than the cosmos itself. This star is…

At a conference on educational physics, someone described a series of multiple-choice problems to test students' ideas about various mechanical phenomena. One of the problems questioned students' conceptions about the shape of the Earth's orbit in the solar system. The question was as follows: "Which of the following schematic illustrations…