This Week's Sky at a Glance, May 31 – June 9

Let's deal with this first. There is no "planet parade" spectacle! Friends and relatives may be asking you about the incredible "Planet Parade" they've heard is happening in the sky. Some internet and "news" outlets are calling it the third great celestial spectacle of this spring after the solar eclipse and the auroras.

Sorry. This is a case of a crazy-weird falsehood ballooning from a tiny kernel of truth and rolling like wildfire through the modern world.

The kernel of truth? This week, the seven planets other than Earth are in a line spanning about 90° along the ecliptic. But most of them are too close to our line of sight to the Sun to be seen at all. Only modest Saturn and Mars are in naked-eye view as dawn begins these mornings. See This Week's Planet Roundup below.

Yet People magazine, to give just one example, is serving this to its 82 million monthly visitors: All About June's Rare 6-Planet Alignment, Including How to See the 'Parade of Planets'. The "dazzling display," People says, "will occur on June 3 in the New York area. It began in a small sector in the São Paulo sky on May 27. ... The planetary parade is predicted to be visible from Sydney on May 28, Mexico on May 29, Abu Dhabi and Hong Kong on May 30 and Athens and Tokyo on June 2. ... The best time to spot them is after sunset or before dawn."

Extrasolar planets, it seems to acknowledge, will sadly be missing: "The naked eye will be limited to the planets viewed from Earth."

The article is so weirdly incoherent that it looks like an AI scraped the web for "planet parade" and hallucinated on the scrapings. Did a human at People even look at it? Welcome to 2024.

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FRIDAY, MAY 31

■ Vega is the brightest star on the northeastern side of the sky. Arcturus is the brightest high overhead. A third of the way from Arcturus to Vega you can find dim Corona Borealis, the semicircular Northern Crown, as shown here:

Corona's one moderately bright star is Alpha Cor Bor, a.k.a. Gemma or Alphecca, magnitude 2.2. But sometime within the next year or so, astronomers expect there may suddenly be two! Because T Coronae Borealis, a famous recurrent nova, shows signs (a gradual dimming) of being about to blow again for its first time since 1946. If it does, if could match the brightness of Alphecca.

Normally T CrB simmers along uneasily at about 10th magnitude. Its explosive rise may take only about a day. Use the finder chart with Bob King's article from 2016. The chart there is detailed enough for identifying T with a telescope even at 10th magnitude.

But no guarantees an eruption will happen anytime soon. That time, it didn't.

■ In early dawn Saturday morning, spot the waning crescent Moon low in the east-southeast almost midway from Saturn, which is upper right of it, to Mars, lower left of it. The planets each appear about 1½ or 2 fists at arm's length from the Moon.

SATURDAY, JUNE 1

■ Constellations seem to twist around fast when they pass your zenith — if you're comparing them to the direction "down." Just a week and a half ago, the Big Dipper floated horizontally in late twilight an hour after sunset (as seen from 40° north latitude). Now it's angled diagonally at that time, as shown below. In just another week and a half, it will hang straight down by its handle!

The farther north you are, the quicker the Dipper seems to gyrate. If, that is, you can judge the location of your zenith point well enough for you to tell the direction "down" accurately so close to it.

■ In early dawn Sunday morning, spot the waning crescent Moon low due east. Look for feeble Mars about 6° or 7° lower left of it (for North America).

SUNDAY, JUNE 2

■ To many people, "Cassiopeia" means "Cold." Late fall and winter are when this landmark constellation stands high overhead. But even on hot June evenings, it still lurks low (as seen from mid-northern latitudes). As twilight fades out, look for Cas down near the north horizon: it's a wide, upright W. The farther north you are the higher it'll appear, but even as far south as San Diego and Atlanta, all of its five bright stars are above the horizon.

MONDAY, JUNE 3

■ With the Moon still out of the evening sky, can you see the big, dim Coma Berenices star cluster? Does your light pollution really hide it, or do you just not know exactly where to look? It's southwest of the zenith these evenings, 2/5 of the way from Denebola (the tip of Leo's tail) to the end of the Big Dipper's handle (the tip of Ursa Major's tail). Its brightest members form an inverted Y. The entire cluster is about 4° or 5° wide — a big, very dim glow in a moderately dark sky, and a speckly glow in a black sky. It nearly fills a binocular's view.

TUESDAY, JUNE 4

■ After nightfall is complete, Vega is the brightest star very high in the east. Barely lower left of it is 4th-magnitude Epsilon Lyrae, the Double-Double. Epsilon forms one corner of a roughly equilateral triangle with Vega and Zeta Lyrae. The triangle is less than 2° on a side, hardly the width of your thumb at arm's length.

Binoculars easily resolve Epsilon. And a 4-inch telescope at 100× or more should resolve each of Epsilon's wide components into a tight pair.

Zeta Lyrae is also a double star for binoculars; much tougher, but plainly resolved in a telescope.

Delta Lyrae, below Zeta, is a much wider and easier pair, reddish orange and pale blue.

WEDNESDAY, JUNE 5

■ Bright Arcturus, magnitude 0, shines pale yellow-orange high overhead toward the south these evenings. The kite shape of Boötes, its constellation, extends from Arcturus. The kite is narrow, slightly bent, and 23° long: about two fists at arm's length. See the illustration under May 31 above.

THURSDAY, JUNE 6

■ For much of the spring at mid-northern latitudes, the Milky Way lies right down out of sight all around the horizon. But watch the east now. The rich Cepheus-Cygnus-Aquila stretch of the Milky Way starts rising up all across the east late these nights, earlier and higher each week. A hint for the light-polluted: It runs horizontally under Vega, along the bottom of the Summer Triangle.

■ New Moon (exactly new at 8:38 a.m. EDT).

FRIDAY, JUNE 7

■ The waxing crescent Moon returns to the evening sky, crossing the upright Gemini twins as they set for the season, as shown below. This evening the low, thin crescent is only 1½ days old.

SATURDAY, JUNE 8

■ The crescent Moon forms a roughly right triangle with Pollux and Castor over it, as shown above. How perfect the right triangle is will depend on your location. Hint: If you're in the Mountain time zone, examine the triangle really carefully.

SUNDAY, JUNE 9

■ The Big Dipper has now swung around to hang down by its handle high in the northwest after dark. The middle star of its handle is Mizar, with tiny little Alcor right next to it. On which side of Mizar should you look for Alcor? As always, on the side toward Vega! Which is now the brightest star in the east.

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This Week's Planet Roundup

Mars and Saturn are in nice view just as dawn begins. The highest and easiest is Saturn, in the southeast. It's magnitude 1.2, fairly modest, but there's nothing else that bright anywhere near it. Its background is dim Aquarius.

Look for Mars far lower left of Saturn, by three or four fists at arm's length. It's magnitude 1.1, and again, nothing else around it is as bright. Mars lies in dim Pisces.

Mercury, Venus, Jupiter, Uranus, and Neptune are veiled by the Sun's glare.

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All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Daylight Time (EDT) is Universal Time minus 4 hours. UT is also known as UTC, GMT, or Z time.

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Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For a more detailed constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a much more detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows all stars to magnitude 7.6.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. (Sadly, it's currently out of print.) The next up are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75). And read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet, the preferred tools for many observers these days, as it does to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner. The top of the hill for total astro-geeks is the Annals of the Deep Sky series, currently at 10 volumes as it slowly works forward through the constellations alphabetically. So far it's only up to F.

Can computerized telescopes replace charts? Not for beginners I don't think, and not for scopes on mounts and tripods that are less than top-quality mechanically. Unless, that is, you prefer spending your time getting finicky technology to work rather than learning the sky. And as Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."

If you do get a computerized scope, make sure its drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).

However, finding faint telescopic objects the old-fashioned way with charts isn't simple either. Learn the essential tricks at How to Use a Star Chart with a Telescope. It applies just as much to charts on a tablet or phone as to charts on paper.

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Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the naked-eye heavens above. It's free.

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"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
            — Carl Sagan, 1996

"Facts are stubborn things."
            — John Adams, 1770

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1. "...because photons do not experience time at all." That is because they travel at the speed of light. As Einstein's Special Relativity showed more than a century ago, time contracts for an object in motion. The time compression approaches infinity as the speed approaches the speed of light.

For instance, the very highest-energy cosmic-ray particles — moving extremely close to the speed of light — may come from active galactic nuclei tens of millions of light-years away. If so, they have taken tens of millions of years to get here. But in their own reference frame, they left only about 20 minutes ago! They are about 20 minutes old. A particle traveling at the speed of light ages not at all. To it, all time is a single instant of zero duration.

Only a massless particle like a photon travels at the speed of light. Any free massless particle must do so. Because if it had any intrinsic mass ("rest mass"), that mass at lightspeed would become infinite. And physicists/cosmologists will insist that no finite region, such as our observable universe, can contain any physically real infinite quantity of any kind whatsoever.

Neutrinos were also once thought to be massless, like photons. But starting around 1998 (as followed in S&T), physicists were shocked to discover that neutrinos streaming past Earth from the core of the Sun change form, or "oscillate," between three different varieties. That means they must experience time, in order to have time to do anything. So they cannot be massless. (Neutrino masses have since been measured. They are extremely slight, somewhat less than 1 electron-volt, roughly a millionth the mass of the electron, the next particle up the mass scale.)

The photon remains the only confirmed massless particle. But the gluon is very likely to be another, and so would the graviton if it exists.

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