•
Why is Antarctica colder? It's a high-altitude continent covered by
a massive ice sheet. The air is dry and thin, providing a very poor
insulating effect. In contrast, the Arctic is the Arctic Ocean. Water has
a much higher heat capacity than land; even when frozen, the ocean
below provides some residual heat.
In your hypothetical scenario, with the Arctic receiving no sun for
three years, it would lose all solar energy input, creating conditions
far more severe than Antarctica.
2. The Cooling Process and the Limit
A planet's surface temperature is a result of its "energy budget" – a
balance between incoming and outgoing energy. Without the sun,
there is only "outgoing" energy (radiating heat into space) with
almost no "incoming."
•
Phase 1: Rapid Cooling: In the first few months, the surface and
atmosphere would cool at an unprecedented rate. Temperatures
would quickly plunge far below the lowest records in Antarctica.
•
Approaching the Radiative Equilibrium Limit: An object
constantly losing heat through radiation will keep cooling until the
heat it radiates away equals the heat it gains from other sources. For
the Arctic, these other heat sources include:
o •
Geothermal heat from Earth's interior: Heat conducted through
the crust. This amount is minuscule (~0.1 W/m²) and almost
negligible.
o
o •
Heat from the ocean below: Even with the surface frozen,
relatively warmer deep-ocean water (though only around -2°C to 1°C)
would slowly transfer heat upward through conduction and
convection. This is the primary factor preventing temperatures
from dropping infinitely.
o
o •
Atmospheric heat transport from lower latitudes: Atmospheric
and ocean currents (like the North Atlantic Current) would still
attempt to transport some heat toward the Arctic. However, facing an
"ice-locked" Arctic, these warm, moist air masses would rapidly cool
and sink, potentially creating an incredibly powerful polar cold high-
pressure system that might actually impedeheat transfer.
o
Based on these factors, scientists have built models. If the sun were
suddenly extinguished, Earth's globalaverage temperature would
eventually stabilize around -160°C to -200°C (similar to Pluto's
surface temperature). However, it would take decades or even
centuries to reach this global equilibrium.
For a scenario limited to just the Arctic region and for only three
years, it would not cool to the temperature of deep space. The
surrounding "warmer" regions and the ocean would provide some
weak but crucial heat input, preventing it from reaching the ultimate
theoretical minimum, but still allowing it to reach the profoundly
frigid temperatures estimated above.
✅ Statement 3:
"Using bond enthalpy to estimate ΔH is generally more accurate than using group
additivity to estimate ΔH"
❌ Answer: False
Explanation:
Group additivity methods are generally more accurate because they account for
molecular structure and interactions more specifically than average bond enthalpies,
which are rough estimates.
✅ Statement 4:
"The second law of thermodynamics tells us about how to measure/calculate
changes in entropy but does not provide absolute entropies."
❌ Answer: False
Explanation:
The third law of thermodynamics tells us that the entropy of a perfect crystal at 0 K
is zero, which allows for absolute entropy values.
The second law focuses on ΔS and spontaneity.
Statement of Interest (Graduate
Training Pathway)
I am deeply interested in pursuing a Doctor of Dental Surgery (DDS) degree, aiming
to become a compassionate and skilled dental professional. My passion for dentistry
stems from a desire to improve oral health outcomes and enhance patients' quality
of life. Through shadowing experiences and volunteer work in community clinics, I've
witnessed the profound impact that dental care can have on individuals' overall well-
being. I am particularly drawn to programs that emphasize community service,
innovative research, and comprehensive clinical training. My goal is to serve diverse
populations, advocate for preventive care, and contribute to advancements in dental
science.
Statement of Intent (CV Development Goals)
To strengthen my CV in preparation for dental school
applications, I plan to gain additional shadowing experience in
both private dental practices and community clinics, with a
focus on observing different dental specialties. I also aim to
participate in volunteer opportunities that promote oral health
education and provide services to underserved populations. If
possible, I would like to join an undergraduate research project
related to oral health or biomedical sciences to further enhance
my academic profile. In addition, I hope to improve my
communication and interpersonal skills, as these are critical for
building strong patient relationships in dentistry. Ultimately, I
want my CV to reflect a well-rounded and committed applicant
who is fully prepared for the challenges and responsibilities of
dental school.
This is a fascinating hypothetical question! It touches on core
principles of Earth science and physics.
The short and direct answer is: The average annual temperature
at the North Pole would likely plummet to approximately -
90°C to -100°C (or even lower), with the coldest winter core
regions potentially briefly approaching -130°C.
However, this is just an estimate based on models and known data.
To understand this number, we need to break down the process:
1. Real-World Reference: Antarctic vs. Arctic
•
The Antarctic: The Antarctic continent is Earth's "cold pole." On the
inland plateau during the long polar night, temperatures can drop to -
80°C to -90°C. The lowest natural temperatures ever recorded on
Earth are -89.2°C (Vostok Station, 1983) and -94.7°C (measured via
satellite remote sensing).
