A C H I E V E
here is a collection of things I like to think about
We just returned from an extended weekend on Cape Cod. That moment when you cross the bridge to the Cape, it feels like you are a million miles away. I love it there.
(all photographs edited using a beta version of the upcoming Rebecca Lily Pro Set III)
Because the Moon is tidally locked, it was not until 1959 that the farside was first imaged by the Soviet Luna 3 spacecraft (hence the Russian names for prominent farside features, such as Mare Moscoviense). And what a surprise - unlike the widespread maria on the nearside, basaltic volcanism was restricted to a relatively few, smaller regions on the farside, and the battered highlands crust dominated. Of course the cause of the farside/nearside asymmetry is an interesting scientific question. Past studies have shown that the crust on the farside is thicker, but why is the farside crust thicker? This mystery is called the Lunar Farside Highlands Problem.
Now scientists may have solved the 55-year-old mystery. The general consensus on the moon’s origin is that it probably formed shortly after the Earth and was the result of a Mars-sized object hitting Earth with a glancing, but devastating impact. This Giant Impact Hypothesis suggests that the outer layers of the Earth and the object were flung into space and eventually formed the moon. The moon, being much smaller than Earth cooled more quickly. Because the Earth and the moon were tidally locked from the beginning, the still hot Earth — more than 2500 degrees Celsius — radiated towards the near side of the moon. The far side, away from the boiling Earth, slowly cooled, while the Earth-facing side was kept molten creating a temperature gradient between the two halves. This gradient was important for crustal formation on the moon. The moon’s crust has high concentrations of aluminum and calcium, elements that are very hard to vaporize.
Aluminum and calcium would have preferentially condensed in the atmosphere of the cold side of the moon because the nearside was still too hot. Thousands to millions of years later, these elements combined with silicates in the moon’s mantle to form plagioclase feldspars, which eventually moved to the surface and formed the moon’s crust. The farside crust had more of these minerals and is thicker.
The moon has now completely cooled and is not molten below the surface. Earlier in its history, large meteoroids struck the nearside of the moon and punched through the crust, releasing the vast lakes of basaltic lava that formed the nearside maria that make up the man in the moon. When meteoroids struck the farside of the moon, in most cases the crust was too thick and no magmatic basalt welled up, creating the dark side of the moon with valleys, craters and highlands, but almost no maria.
Credit: ESO/M. Kornmesser, Penn State/A’ndrea Elyse Messer
What is the Difference Between Warm-Blooded and Cold-Blooded Animals?
Cold-blooded animals are those whose body temperatures are regulated by their environment, and warm-blooded animals are those whose body temperatures are kept relatively constant by internal mechanisms. Along with the way their body temperatures vary, another main difference between these types of animals is that warm-blooded animals require more food. The terms “cold-blooded” and “warm-blooded” are misleading because cold-blooded animals’ blood is not necessarily cold, it just varies based on the temperature of the environment. More accurate terms are “ectothermic” instead of “cold-blooded” and “endothermic” or “homeothermic” instead of “warm-blooded.” Another term for ectothermic animals is “poikilotherms,” which means animals that have varying body temperatures.
Examples and Exceptions
The vast majority of mammals and birds are warm-blooded, and almost all reptiles, fish, insects, amphibians and arachnids are cold-blooded. There are some exceptions, however, and some animals that have characteristics of both types. For example, bats and mole rats are mammals, but their body temperatures can vary according to their environments, especially when they are not active. Certain insects, such as hawk moths and some bees, can raise their body temperatures by beating their wings. Some fish have internal mechanisms that help keep their brains and eyes from becoming too cold, which might impair their function.
One significant difference between warm-blooded and cold-blooded animals is that warm-blooded animals typically need three to 10 times as much food to survive, because they must create their own body heat. Accordingly, these endothermic animals must be three to 10 times as good at obtaining food, putting them on a different metabolic and evolutionary level. Ectotherms can rely on sunlight and other environmental factors to provide heat, rather than needing to create it themselves, so their bodies need less food.
Some Advantages and Disadvantages of Each
There are several advantages to being endothermic — greater stamina, having only one set of body enzymes that works optimally at a set temperature and the ability to increase body temperature during freezing weather. A spider that is caught in a blizzard will freeze solid, but a human being has at least a chance of survival. Ectothermic animals need to maintain several sets of enzymes for their biological processes because enzymes are sensitive to temperature, but endothermic animals can maintain one set.
The most useful advantage of being endothermic is greater stamina. An endothermic creature can outrun a cold-blooded predator as long as it avoids the initial attack. Warm-blooded predators can outrun their ectothermic prey, and endothermic animals can forage for a longer time. Some people might say that endothermic creatures are superior because they tend to have more stamina, but they cannot move faster than cold-blooded animals for short bursts, and they starve far more easily than ectothermic creatures.
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'You could've taken anyone!’ said Ron in disbelief over dinner. ‘Anyone! And you chose Loony Lovegood?’
'Don't call her that, Ron,' snapped Ginny, pausing behind Harry on her way to join friends. 'I'm really glad you're taking her, Harry, she's so excited.'
as always, who is sentimental about their friendship? Not me, of course