The secretary desk was probably made in the USA in the 1920s. Nothing special. Here is what the keyhole looks like, with the escutcheon plate removed. How do I find the right key?
The nail has rectangular cross-section and isn't very pointy. Flat on the pointy end, actually. Probably made in the USA. The head is slightly angled. I can't tell if it got bent or was made that way. 2.5 inches (64 mm) long. Not rusted. What is/was this kind of nail for?
The secretary desk was probably made in the USA in the 1920s. Nothing special. In case it helps, here is what the keyhole looks like, with the escutcheon plate removed. Paperclip hasn't got me anywhere. I don't know much about lockpicking. How do I find the right key?
Was one particular species of bird the ancestor of all birds?
Was one particular species of dinosaur the ancestor of all birds?
Was one particular species of something between dinosaurs and birds the ancestor of all birds?
Or did different clades of birds originate from different ancestors that were not birds?
When did birds separate from all other dinosaurs?
How much do we know about the ancestors of birds?
In Hubble Space Telescope photos of other galaxies, I see many small bright dots that I take to be individual stars, and large areas of brightness that I take to be nebulae. To what extent are my interpretations correct? How much of the light comes directly from stars, and how much is starlight reflected by nebulae? How much of the light is from emission nebulae? How much of what looks like nebulae is actually vast numbers of stars that are not individually resolved?
I have a Samsung phone made in 2015 which can no longer make phone calls, but otherwise works fine. It has Android 5.0.2. I'm surprised to discover that the calculator apparently has no trig functions. Am I looking in the wrong place? Do newer versions have trig functions?
I drew diagrams of some waves. These could be representations of sound intensity over time, measured at a point in space, or maybe sound intensity over space, measured at a point in time. At the bottom is a continuous sine wave, which would have the sound of a steady tone. Can you tell me what the three short pulses might sound like?
