Viranga Perera

and 3 more

Anorthosites that comprise the bulk of the lunar crust are believed to have formed during solidification of a Lunar Magma Ocean (LMO) in which these rocks would have floated to the surface. This early flotation crust would have formed a thermal blanket over the remaining LMO, prolonging solidification. Geochronology of lunar anorthosites indicates a long timescale of LMO cooling, or re-melting and re-crystallization in one or more late events. To better interpret this geochronology, we model LMO solidification in a scenario where the Moon is being continuously bombarded by returning projectiles released from the Moon-forming giant impact. More than one lunar mass of material escaped the Earth-Moon system onto heliocentric orbits following the giant impact, much of it to come back on returning orbits for a period of 100 Myr. If large enough, these projectiles would have punctured holes in the nascent floatation crust of the Moon, exposing the LMO to space and causing more rapid cooling. We model these scenarios using a thermal evolution model of the Moon that allows for production (by cratering) and evolution (solidification and infill) of holes in the flotation crust that insulates the LMO. For effective hole production, solidification of the magma ocean can be significantly expedited, decreasing the cooling time by more than a factor of 5. If hole production is inefficient, but shock conversion of projectile kinetic energy to thermal energy is efficient, then LMO solidification can be somewhat prolonged, lengthening the cooling time by 50% or more.

Viranga Perera

and 5 more

Informal education can be a vital part of a person’s learning experience, thus it is important to continue studying its effectiveness and consider improvements. To that end, we studied participants who built their own AM radio at three School of Earth and Space Exploration open house events at Arizona State University. For this qualitative research study, we audio recorded and transcribed interviews of 41 adults after they completed the activity. Median duration of interviews was 3 minutes. Based on their responses, we categorized participants as either a parent who brought their children (Np = 23) or an individual (Ni = 18). This is consistent with previous studies since over 50% of participants are typically parents. We further grouped each category based on their Science, Technology, Engineering & Math (STEM) background: No STEM Background (NSB), Some STEM Background (SSB) and Expert Electronics Background (EEB). STEM backgrounds of parents were evenly distributed, with each group (i.e., NSB, SSB & EEB) accounting for about 30%. In contrast, about 60% of individuals were in the SSB group. Regardless of STEM background, the vast majority of parents stated that they came to the activity because of their children. Additionally, a majority of participants stated that they learned something from the activity, with only 4 of 41 participants saying they did not learn anything. Thus, this activity provides learning opportunities for people of all STEM backgrounds. As an example, one individual in the EEB group stated, “The design of the transmitter and the receiver itself is completely complicated based on me studying for 10 years trying to understand what a transmitter and receiver is. But just in five minutes I found that I could really built [sic] it by myself.” Yet, individuals who are either in the NSB or the EEB group may be overlooking certain informal education opportunities, since together they accounted for only 40% of individuals. To improve public understanding of science, informal learning centers should continue to consider ways to make events more accessible and more enticing for people who may not be experiencing these valuable learning opportunities.