Last Seen In 1986, Halley’s Comet Will Make Its Presence Known This Week With Shooting Star Show

Will you be alive in 2061? If not, your only chance to see something of Halley’s Comet comes in both early May and late October each year when Earth moves through streams of particles the great comet deposited in the solar system in 1986.

As those particles hit Earth’s atmosphere they energise and glow for a millisecond, something that happens as many as 40 times per hour to create a meteor shower. That’s what is happening on Monday/Tuesday as the Orionid meteor shower peaks after midnight.

What has Orion got to do with this meteor shower?

Technically speaking, nothing whatsoever. The Orionid meteor shower gets its name from the constellation its shooting stars appear to come from—Orion the Hunter. Astronomers call this the “radiant point”, which more precisely is close to an open cluster of stars called Collinder 69. A lovely sight though binoculars and easy to see with the naked eye from a dark sky site, Collinder 69 can be found just above Orion the Hunter’s head. However, just look in the general direction of Orion’s Belt and you’ll see any shooting stars from the Orionid meteor shower.

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When, where and how to see the Orionids?

Although it runs from October 2 through November 7, the night to watch for shooting stars from the Orionid meteor shower is Monday through Tuesday, October 21 and 22, 2019. The best time will be after midnight when your location will be on the nightside of Earth. A lawn chair or deckchair is perfect for watching meteor showers, though the best advice is always to wrap up warm and let you eyes adjust to the dark and just watch the night sky (in this case, look generally southeast towards Orion). Whatever you do don’t stop looking, and absolutely do not look at your smartphone. Its white light will instantly kill your night vision.

Visible from both hemispheres, the Orionids—and any moonless meteor shower—is best enjoyed under a dark country sky. If that’s not going to be possible, make sure there are no artificial lights in your line of sight, and even better, find a place in shadow from any artificial lights.

How to find a dark sky

About 40km from a town is where to go. Here are some great resources to help you find a dark sky near you:

What is Halley’s Comet?

Every 75 years a 15x8km comet enters the solar system and becomes visible to the naked eye from Earth. The only known short-period comet that can be seen twice in one lifetime (if observed when very young), its arrival was first predicted by British astronomer Edmond Halley, who calculated that it would appear in 1758. It duly did, though 16 years after his death. Halley also discovered that transits of Mercury and Venus across the sun could be used to calculate the size of the solar system.

When is the Halley’s Comet meteor shower in May?

That would be the Eta Aquarids, a meteor shower that will peak on May 5/6 in 2020, though it’s not as dependable a meteor shower as the Orionids.

Wishing you clear skies and wide eyes.

Follow me on Twitter. Check out my website.

I’m an experienced science, technology and travel journalist interested in space exploration, moon-gazing, exploring the night sky, solar and lunar eclipses, astro-travel, wildlife conservation and nature. I’m the editor of and the author of “A Stargazing Program for Beginners: A Pocket Field Guide” (Springer, 2015), as well as many eclipse-chasing guides.

Source: Last Seen In 1986, Halley’s Comet Will Make Its Presence Known This Week With Shooting Star Show

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Scientists Weighed All The Mass In The Milky Way Galaxy It’s Mind Boggling

Something weird is happening in our galaxy: It’s spinning fast enough that stars ought to be flying off, but there’s something holding them together.

The substance that acts as a gravitational glue is dark matter. Yet it’s incredibly mysterious: Because it doesn’t emit light, no one has ever directly seen it. And no one knows what it’s made of, though there are plenty of wild hypotheses.

For our galaxy — and most others — to remain stable, physicists believe there’s much, much more dark matter in the universe than regular matter. But how much?

Recently astronomers using the Hubble Space Telescope and the European Space Agency’s Gaia star map attempted to calculate the mass of the entire Milky Way galaxy.

It’s not an easy thing to do. For one, it’s difficult to measure the mass of something we’re inside of. The Milky Way galaxy measures some 258,000 light-years across. (Recall that one light-year equals 5.88 trillion miles. Yes, the galaxy is enormous.) And an abundance of stars and gas obscures our view of the galactic center. The team of astronomers essentially measured the speed of some objects moving in our galaxy and deduced the mass from there (the more massive the galaxy, the faster the objects should move.)

Their answer: The galaxy weighs around 1.5 trillion solar masses. This number helps put in perspective how very small we are.

Take, for instance, where stars in the Milky Way fit in.

If you’re lucky enough to get a completely dark, clear sky for stargazing, it’s possible to behold as many as 9,000 stars above you. That’s how many are visible to the naked eye. But another 100 billion stars (or more) are out there just in our own Milky Way galaxy — yet they’re just 4 percent of all the stuff, or matter, in the galaxy.

Another 12 percent of the mass in the universe is gas (planets, you, me, asteroids, all of that is negligible mass in the grand accounting of the galaxy). The remaining 84 percent of the matter in the galaxy is the dark matter, Laura Watkins, a research fellow at the European Southern Observatory, and a collaborator on the project, explains.

The enormity of the galaxy, and the enormity of the mystery of what it’s made of, is really hard to think through. So, here, using the recent ESA-Hubble findings, we’ve tried to visualize the scale of the galaxy and the scale of the dark matter mystery at the heart of it.

As a visual metaphor, we’ve constructed a tower of mass. You’ll see that all the stars in the galaxy just represent a searchlight at the top of the building. The vast majorities of the floors, well, no one knows what goes on in there.

The mass of the Milky Way, visualized

To visualize the mass of 1.5 trillion suns, let’s start small. This is the Earth. It has a mass of 5.972 × 10^24 kilograms.

This is the Earth compared to the sun. The sun is 333,000 times more massive than Earth.

Now let’s try to imagine the mass of the 100 billion stars (or more) stars in the Milky Way galaxy.

That’s enormous.

Another 12 percent** of the mass in the galaxy is just gas floating between stars (mostly hydrogen and helium).

Here’s what the gas looks like using this same visual scale.

What about black holes? “It’s a bit harder to put an exact number of how much they contribute to the total mass, as we don’t know how many there are, but it will be a very, very very small fraction,” Watkins explains. “The supermassive black hole at the center of the Milky Way is around 6 million solar masses,” which is really tiny on the scale of the entire mass of the galaxy.

And it’s tiny on the scale of the most abundant, mysterious matter in the galaxy: the dark stuff. Again: 84 percent of the galaxy is made up of dark matter.

Dark matter doesn’t seem to interact with normal matter at all, and it’s invisible. But our galaxy, and universe, would fall apart without it.

Scientists hypothesized its existence when they realized that galaxies spin too quickly to hold themselves together with the mass of stars alone. Think of a carnival ride that spins people around. If it spun fast enough, those riders would be ripped off the ride.

Accounting for “dark matter,” and the gravity it generates, made their models of galaxies stable again. There’s some other evidence for dark matter, too: It seems to produce the same gravitational lensing effect (meaning that it warps the fabric of spacetime) as regular matter.

Now let’s try to visualize the mass of dark matter, compared to the mass of stars and gas.

And remember: This is just our galaxy. There are some hundreds of billions of galaxies in the universe.

Also remember that dark matter isn’t even the biggest mystery in the universe, in terms of scale. Some 27 percent of the universe is dark matter, and a mere 5 percent is the matter and energy you and I see and interact with.

The remaining 68 percent of all the matter and energy in the universe is dark energy (which is accelerating the expansion of the universe). While dark matter keeps individual galaxies together, dark energy propels all the galaxies in the universe apart from one another.

What you can see in the night sky might seem enormous: the thousands of stars, and solar systems, to potentially explore. But it’s just a teeny-tiny slice of what’s really out there.

**(Clarification: Ari Maller, a physics professor at New York City College of Technology, wrote in, pointing out that the proportions in our graphic —4 percent of the matter in the galaxy being stars, 12 percent gas, and 84 percent dark matter — are a bit off. They do, he says, represent the overall proportions of each in the universe. But, he writes “we don’t live in an average place,” clarifying that instead ”the gas in the Milky Way is only about 10 percent of its mass.”)


Source: Scientists weighed all the mass in the Milky Way galaxy. It’s mind-boggling.

Read more:… The latest weigh-in of our home galaxy shows much less mass from dark matter, which means we may live in a cosmic oddball

Today’s New Moon May End Ramadan And Sets Up Eclipse Of The Sun And ‘Half-Blood Thunder Moon Eclipse’

A passenger jet crosses in front of the crescent moon as seen from Leavenworth, Kan at dusk Sunday, May 28, 2017. (AP Photo/Charlie Riedel)

Today the Moon is not visible. It’s the moment of New Moon exactly as this post was published, the point in our satellite’s orbit when it’s roughly between the Earth and the Sun. The far side of the Moon, only, is illuminated, and it’s invisible to us. However, June’s New Moon is rather special.

For starters, it (almost) signals the end of Ramadan, the “moon-th” long fast between dawn and sunset observed by devout Muslims, which began on May 5, and the beginning of Eid al-Fitr, one of two holy days of the year for the Islamic world. However, it’s technically not until the sighting of the crescent Moon, perhaps today, Monday, June 3, 2019, at dusk, or perhaps tomorrow on Tuesday, June 4, 2019.

The exact time of New Moon is 10:01 Universal Time today on Monday, June 3, 2019, which translates to 11:01 a.m. in London, 06:01 a.m in New York City and 03:01 a.m. in Los Angeles.

However, June’s New Moon also sets up something incredible; a total solar eclipse and a lunar eclipse. In fact, the next time we have a New Moon it will be sitting plum in front of the Sun. By a cosmic coincidence, the Moon is 400 times smaller than the Sun, but the Sun is about 400 times further away.

What is the ecliptic?

The ecliptic is the path the Sun takes through the sky. The Moon, whose orbit is inclined slightly, intersects that line–essentially Earth’s orbital plane–twice each month. Occasionally that means a New Moon covers the Sun exactly, or that a Full Moon drifts into the Earth’s shadow. As such, it’s normal for two or more eclipses to come in succession. That’s what’s about to happen.

A total solar eclipse is seen above the Bald Knob Cross of Peace Monday, Aug. 21, 2017, in Alto Pass, Ill. More than 700 people visited the over 100 foot cross for the event. (AP Photo/Charles Rex Arbogast)

A total solar eclipse is seen above the Bald Knob Cross of Peace Monday, Aug. 21, 2017, in Alto Pass, Ill. More than 700 people visited the over 100 foot cross for the event. (AP Photo/Charles Rex Arbogast)

When is the Total Solar Eclipse?

On July 2, 2019, the New Moon will exactly fit across the Sun as seen from a narrow strip of the Earth’s surface. The path of totality is narrow, around 100km wide, and is mostly over the South Pacific. In fact, only the final few minutes of the event will be visible over land. Eclipse-chasers are heading inland from La Serena in Chile, and Bella Vista in Argentina, to witness the rare event that last happened on August 21, 2017 across the USA.

Earth's shadow moves across the moon late Saturday, Aug. 16, 2008, during a partial lunar eclipse seen from Budaiya, Bahrain, in the Persian Gulf. (AP Photo/Hasan Jamali)

Earth’s shadow moves across the moon late Saturday, Aug. 16, 2008, during a partial lunar eclipse seen from Budaiya, Bahrain, in the Persian Gulf. (AP Photo/Hasan Jamali)


When is the ‘Half-Blood Thunder Moon’ Partial Lunar Eclipse?

On July 16, 2019, a Full “Thunder” Moon will drift into the Earth’s outer shadow. It won’t enter the central shadow, so the Moon won’t go completely “blood red,” but about 65% of it will turn rosy. It will be visible from South America, Europe, Africa, Asia, and Australia, but not North America. This “Half-Blood Thunder Moon Eclipse” promises to be a special event, especially in London, where a “smiley face” half-red moon will rise in the east.

For eclipse-chasers and eclipse-photographers, July can’t come soon enough.

Wishing you clear skies and wide eyes

Follow me on Twitter @jamieacarter@TheNextEclipse or read my other Forbes articles via my profile page.

I’m an experienced science, technology and travel journalist interested in space exploration, moon-gazing, exploring the night sky, solar and lunar eclipses

Source: Today’s New Moon May End Ramadan And Sets Up Eclipse Of The Sun And ‘Half-Blood Thunder Moon Eclipse’

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