It’s always amazed me that Mercury was ever discovered by the ancients. Because it’s so close to the sun (from our viewpoint), it’s only visible to the naked eye for a few days at a time, a few times a year. And even when you know exactly where to look for it, and exactly which days it will be the furthest from the sun (greatest elongation), it’s still very hard to see.
But last night, it was helpfully located at almost greatest elongation just a couple of finger-widths away from the very thin crescent of an almost new moon, and even more rare, there were no clouds in the western sky from my Oregon coast location. And I saw Mercury very clearly with my naked eye for the first time in my life. I’ve tried many times before, but the best I’ve ever done was being able to see it through binoculars, or just barely seeing a glimmer when I didn’t look straight at it.
Last night, for whatever reason, it was so clear and bright that I could even see it through a window screen after I came inside. Just a tiny speck of light in the sky, really nothing compared to Venus or Jupiter or even Sirius, but I’m very happy that I saw it.
Cool! I’m pretty sure I’ve seen Venus. It was close to sunset in November and it was a very bright, fixed object in the sky. I did a Google search and Venus seemed to fit for what I was seeing. I don’t really know how to describe exactly where it was in the sky, but I was facing south and it was kind of to the left. I live in New York and there’s a lot of light pollution, but some stars (and Venus apparently) are visible.
I’ve also seen Saturn through a telescope which was pretty cool. It looked like a little bright outline of itself barely larger than a pencil eraser.
Thanks, Tony. I’ll look for it tonight, if it’s clear here in Kansas.
CatherineZeta, yes, you have surely seen Venus, on many occasions. For several hours before sunrise and after sunset, most nights, it’s BY FAR the brightest thing in the sky after the moon. Much brighter than, say, Sirius, which is the brightest star.
And yes, seeing the disc of Saturn through a telescope is cool. Try Jupiter next time – all you need are binoculars, and you can usually spot several of its four largest moons! They look like pinprick “stars”, lined up on a single plane.
It would be very surprising if you had not seen Venus. I am sure almost everybody has. It is the brightest object in the sky after the moon, and is reasonably high in the sky for much of the time. Sometimes it is very obvious and striking. Jupiter is almost as bright, and I have little doubt that you will have seen it too, even if you did not know it. Saturn and Mars are plenty bright too, and often high in the sky. Big city light pollution is not enough to swamp their light (heck, you can even see Venus sometimes in bright daylight, as a tiny white dot in the blue sky). If you can only see a handful of “stars” in the sky (whether due to city lights or haze), one or two, or more, of them are probably these planets. There are no actual stars anything like as bright as Venus or Jupiter, and only a very few brighter than Mars or Saturn.
Mercury is a different case, because, as TonySinclair points out, it can only ever be seen close to horizon soon after sunset or soon before sunrise, and even then, not for much of the year. In built up, wooded or hilly areas (if you are in a valley) you may not be able to see it, even when it is there, because your view of the horizon area is blocked. Also, when you are looking towards the horizon you are looking through a greater thickness of atmosphere, so mist and air pollution that might not cause you too much of a problem if you were looking high up, may be enough to obscure your view. I think, however, that like Venus, Jupiter, Saturn, and Mars, it is quite bright enough to cut through city light pollution, and even a moderate amount of mist or other gunk in the air, if that is the only issue. I believe I have seen it, looking quite bright, from the suburbs of Los Angeles.
As for the ancients, they did not have to contend with much in the way of light pollution or air pollution, and many of them would have lived in open country (on farms, for instance),and would often have been out until after sunset or before sunrise. I do no think it is at all surprising that they were well aware of Mercury. (And it is not like they had a lot of other options for night time entertainment.)
For the ancients, the hard part about recognizing planets was not in seeing them, but in recognizing that they were planets: that they moved, night by night, against the background of the other stars. In this respect, Mercury was probably the easiest to spot, as it moves the fastest, and may be in a noticeably different position relative to the stars from one night to the next. On the other hand, I believe that Saturn, although brighter than most stars, and often high in the sky, was not recognized as a planet until quite a bit later in ancient times than Mercury, Venus, Mars and Jupiter. This is because it moves so slowly that its movement is only noticeable on a timescale of weeks or even months. Uranus was not recognized as a planet at all in antiquity, although it is visible to the naked eye (if not particularly bright) because it moves so slowly against the starry background that its movement was never noticed.
Be aware that by now, the moon has left it far behind, so it will be much harder to find for you than it was for me.
Here’s a great free program that shows you what the sky will look like any time within reason (a few millenia before or after now) from anywhere on earth. The interface is kind of clumsy, but it’s worth the time to figure it out. Set it for sunset a couple of days ago and you’ll see what I was talking about.
I’m pretty sure you’ve seen Venus, too, because it’s the brightest thing in the sky next to the sun and moon, but what you describe was more likely Jupiter. If it was close to sunset, Venus would have been to your right, not your left, as you looked south. It’s never more than about 47 degrees from the sun. If you imagine looking down on the solar system from above, you can see why. The orbit of Venus is inside of ours, so from the earth, we always have to look in the same general direction as the sun to see it.
Mars, Jupiter, and Saturn have orbits outside of ours, so they shine brightest when they are in the opposite direction as the sun — just like the full moon.
In all seriousness, thank you for pointing out the conditions you need for seeing Mercury - I’m definitely going to have to watch for times when that is possible.
We’ve been completely socked in for more than the week since I learned about that new supernova-it seemed like it was clearing a bit yesterday, but nope-back to overcast skies again.
Ha! Based on this thread, I actually dreamed I was looking up at the sun and seeing Mercury hug close to it and travel across it–and without any corneal or retinal damage!
I did see it, here in Kansas, just two hours ago! Beautiful, clear night. Halfway between the sliver moon and the horizon, and a bit to the right, as the last dusky rose of the recently-set sun tinged the horizon, was a yellow-white pinprick. Beautiful!
It was the only thing in that part of the sky at that moment (several stars were clearly visible in the black, opposite part of the sky.)
