GAINING ON MARS

by William J. Bechaver

The Moon continues on through it’s last leg of the journey amongst the planets. Now past full, it is waning in it’s monthly cycle, and calmly passing into the early morning sky.

For the past three weeks, the Moon has encountered our brightest planets, precisely seven days apart, three Saturdays in a row.

First it was Venus, then last week, Jupiter, now this Saturday, it will encounter Mars.

This indicates that the three planets are spread across the sky, virtually evenly spaced. Since the Moon moves about twelve degrees in a twenty four hour period, this determines that the three brightest planets are about 84 degrees apart, not taking into account the amount they have moved during the intervening weeks. The three are spread across about 170 degrees of sky.

So, when Venus is low in the west, Jupiter will be high in the sky, and Mars low in the East. About six hours later, Jupiter should be at the position in the sky where we first observed Venus, and Mars should be where Jupiter was earlier. Of course, Venus will have set by then, and will be below the horizon.

There is a very short period right now, when both Venus and Mars can be seen in the sky at the same time, and you would need very low, flat, and clear horizons both in the east and in the west to see them.

But, we are still quickly gaining on Mars, so the red planet rises a little earlier each night. If you will remember, the Moon encountered Mars on June 3rd. And they will again be close on the evening of Saturday 30 June. So, we are gaining about four days on Mars every month.

This month’s second encounter won’t be quite as close as the one earlier. The Moon will rise with Mars at about ten o’clock Saturday night. Notice how much brighter Mars has become in the past month, and note the noticably ruddy hue of the decidedly red planet.

We continue to gain on Mars in our orbit. We travel around the Sun at a greater speed, and we are closer to the Sun, so have a shorter distance to travel.

We will be at our closest to Mars in late July. When we began keeping track of our progress seven weeks ago, we were 72 million miles from Mars. This weekend, when we observe the red planet rising with the Moon, we will be less than 42 million miles away. We are an astounding 30 million miles closer to Mars than we were a mere seven weeks ago! And we are less than half the distance from Mars than we are from the Sun.

In fact, since we observed Mars with the Moon earlier in the month, it has increased in brightness by almost one magnitude, as we are 15 million miles closer than we were when the month began.

Thanks for your continued interest in our astronomy columns. If you have any questions or article requests, contact us at spacescape@rocketmail.com, or follow us on Twitter @ColoSpacEScapE for updates and additional viewing opportunities.

• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.

THE GAS GIANTS DOMINATE THE NIGHT

by William J. Bechaver

As the Moon continues waxing through its lunar cycle, this week, it encounters the two largest planets in our solar system.

This week, the two largest gas giants take center stage in our planetary tour.

Jupiter is by far the largest planet in our solar system. It is mostly comprised of gases, as are all of the large outer planets.

Jupiter is a huge, swirling ball of gas, much further away than is Mars. But even though it’s more than nine times more distant than the red planet, it remains brighter in the night sky.

One reason Jupiter remains so dominant is the composition of its clouds. The gases that comprise Jupiter are very light, reflecting much of the sunlight back toward Earth.

Also, Jupiter is much larger than Mars. Mars is a small, red rocky world in space, only about half the size of Earth, or about twice the size of our tiny Moon. Jupiter is an astounding twenty one times larger than is Mars.

It is more than eleven times larger than our home planet. So, even being almost ten times further away than Mars, it remains brighter in the sky, and actually appears more than twice as large as Mars when viewed in a telescope.

We can use the Moon to find Jupiter this week, as our tour amongst the planets continues. On the night of Saturday 23 June, the Moon will be in the neighborhood of Jupiter, just over four degrees above the gas giant as the Sun sets.

Watch the pair throughout the night, as they will be visible until early the next morning, and the gap between the two will slowly increase, as the Moon moves in its orbit around Earth.

Saturn, the second largest planet in the solar system, rises into prominence during the night of Wednesday 27 June. That is the night when Saturn will lie in opposition, or in a position in the sky opposite the Sun when viewed from Earth.

Two significant facts are determined by that prominent position. Saturn will rise in the east just as the Sun is setting in the West. Therefore, Saturn will remain visible the entire night, not setting until the Sun is rising.

Secondly, since it is opposite the Sun in the sky, it means it is on the same side as Earth in its orbit, so on the night of opposition, we will be closest to Saturn, and closer than we will be to it for more than a year.

Though Saturn is also much larger than Mars, though not as large as Jupiter, it is much further away. Jupiter is almost ten times further than Mars, but Saturn, the next planet out, is more than twice as far as Jupiter from us, or almost 19 times further than Mars.

So, Saturn will be over an astounding 841 million miles from Earth, and that’s the closest we will ever be to Saturn this year. At that distance, it takes the light reflected by Saturn, more than an hour and a quarter to reach us here on Earth.

Even so, at that distance, Saturn remains bright. Though not as bright as Mars, when viewed through a telescope, the planet appears almost as large as Mars. So expansive is the ring system that surrounds Saturn, they appear much larger than Mars, and nearly as large as Jupiter, even at that vast distance.

Saturn will also be highlighted this week, as on the night of opposition, Wednesday 27 June, the full Moon will join it. The two will be separated by less than two degrees at midnight, when the two will lie almost directly overhead.

So, it is a spectacular week for the two largest gas giant planets of our solar system, as the Moon moves amongst them, pointing them out to us.

But nothing remains as impressive right now as the planet Mars. The Moon will pass by at the end of the month, and we’ll take a closer look at our nearest neighbor then.

But the Mars watch continues as well, as we are still gaining on it for a closest encounter at the end of July.

When we began our tracking of the red planet last month, we were at a distance of about 72 million miles away. This weekend, when we look at the red jewel in the early morning sky, we will be under 45 million miles away!

So, get out on the weekend, and next week, to check out the largest planets in our skies, and while you’re out there, don’t forget to look to the east, and locate brilliant red Mars, as it continues to brighten in our early morning skies!

Thanks for the positive feedback about our featured columns, and your continued interest in astronomy. If you have any questions or article requests, contact us at spacescape@rocketmail.com, or follow us on Twitter @ColoSpacEScapE for updates and additional viewing opportunities.

• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.

PLANETARY TOUR BEGINS WITH VENUS

by William J. Bechaver

It just so happens that all of the major visible planets are moving into the night sky right now, to make viewing them easier, and definitely more convenient.

With the Moon having several nice close encounters with all of them during the lunar cycle this month, it is a perfect opportunity to have it guide us on our way as we tour the planets.

This week, we will begin with Venus, as there will be two opportunities for us to see it in a nice pairing with the Moon.

On the evening of Friday 15 June, go out just after sunset and look to the west. High in the western sky you will see a beautiful thin, upturned crescent Moon, with brilliant Venus up above it. It will be the most beautiful gathering of the two evenings.

During the intervening twenty four hours, the Moon will actually pass closer to Venus, within about two degrees, but the closest of the encounter will come during our daylight hours, when both the Moon and Venus are on the other side of our planet.

By the time they are visible again the following evening, the Moon will have moved higher into the sky, and off to the south of Venus. On the evening of Saturday 16 June, the Moon will be about the same distance from Venus, but up to the left.

During the day, Venus moves very little in our sky, so if you look at the pairing both evenings, right after sunset, you can see how far the Moon moves across the sky in just one day, having been below Venus on Friday and equally above it on Saturday evening.

Either way, it will be a beautiful conjunction between the brightest planet in the sky and our nearest companion, the upturned crescent Moon.

Folklore would tell us that we will have a drought when the Moon’s crescent is turned upward, like a bowl, indicating that it is holding water.

One week from Saturday, the Moon will be in conjunction with Jupiter, so we’ll take a closer look at the largest planet in our solar system next week, in preparation for that close encounter.

We are still gaining on Mars in its orbit, when we will be closest to the red planet at the end of July.

When we began our watch last month, we were approaching Mars at a distance of about 72 million miles. Two weeks ago, we had closed the gap by 15 million miles, when we were only 57 million miles away. This week, we have closed the space further, and we are just under 48 million miles from Mars right now! We are about half as far from it as we are from the Sun.

Mars is our nearest neighbor in the solar system right now, beyond our companion Moon. Though the orbit of Venus comes closer to ours, right now, Venus is at an angle to the Sun, which allows us to see it so brilliantly in the evening sky. With it on a further side of its orbit right now, Venus is about 108 million miles from the Earth. About 15 million miles further than the Sun.

Mercury, which has the potential to be closer also, is far on the other side of the Sun right now, and lost in the solar glare.

So, as we begin our summer tour amongst the planets, get out there Friday and Saturday evening to see magnificent Venus with the Moon, as we prepare for a wonderful season of planet views!

Thanks for the positive feedback about our featured columns, and your continued interest in astronomy. If you have any questions or article requests, contact us at spacescape@rocketmail.com, or follow us on Twitter @ColoSpacEScapE for updates and additional viewing opportunities.

• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.

SUMMER MARS WATCH CONTINUES

by William J. Bechaver

As I said a couple of weeks ago, the Earth is quickly gaining on Mars in its orbit, and we are rapidly closing on the red planet.

The climax of the chase will come next month, when we are closest to Mars, and the red planet will shine brightly in our night sky.

But right now, the planet has been brightening greatly in our early morning sky, since its conjunction with Saturn in early April. Now it is a beautiful ruby gem, and the Moon will point the way to make finding it easy this week.

On the early morning of Sunday 3 June, the waning gibbous Moon will lie only a few degrees from the planet Mars. The two will rise together in the east just before midnight on Saturday night. As they climb higher into the sky, the gap between the two will slowly close.

Watch the amazing Martian display throughout the early morning hours, until the Sun has brightened the sky. By then, the pair will have climbed high into the sky, making an amazing spectacle of the silvery Moon with the ruby red Mars.

Of course, the Moon only appears closer to Mars. The entire time, both the Earth with the Moon is gaining on the further planet in its orbit.

Three weeks ago, when we began our Martian watch, we were a mere 72 million miles distant from Mars. But now this week, we are only 57 million miles from it! Why are we gaining so quickly.

For one, Earth is closer to the Sun, so our orbit is much shorter than is that of Mars, so we have the inside track for the race. And secondly, we travel more rapidly in our orbit, since we are closer to the Sun and propelled by its gravity.

Mars is currently speeding along at just under 16 miles per second in its orbit, but we are traveling just over 18 miles per second in ours. That doesn’t seem like much, but taken in the course of twenty four hours, we travel about 172,800 miles more than Mars every day, so we won’t be left behind for long, even with Mars being 57 million miles away.

We will be at our closest approach to Mars in about a month, so we will keep an eye on the prize in the sky, and watch as it grows brighter progressively during the next month, and we finally overtake it in our orbit.

Thanks for the positive feedback about our featured columns, and your continued interest in astronomy. If you have any questions or article requests, contact us at spacescape@rocketmail.com, or follow us on Twitter @ColoSpacEScapE for updates and additional viewing opportunities.

• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.