Of Particular Significance

Category: Astronomy

Northern Lights Possible Tonight

2ND UPDATE: Auroras are indeed being observed. (I myself am a bit too far south and skies are hazy, making the moonlight blinding; but I am reading reports from northern Europe.)

UPDATE: Something has happened at the ACE satellite around 2300 UTC (0100 Europe time, 7 pm New York time. See the plot added to the bottom of this post.

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Still waiting for a possible outbreak of auroras (northern/southern lights) tonight; a tremendous blast from the Sun, launched from a sunspot two days ago, is believed likely to make a glancing impact on the Earth, and to do so within the next 12 hours or so. That means a possibility of bright northern lights tonight if you’re north of, say, New York City’s latitude.

BUT always keep in mind that forecasting auroras is part science, part art, part luck. Our chances are decent, but the forecast can always be wrong.

As far as timing, the best way to monitor what’s going on, I’ve found, is to use https://www.swpc.noaa.gov/products/ace-real-time-solar-wind and look for sudden activity in multiple data channels. If that happens, then the ACE satellite (about a million miles away) has detected a sudden change in the solar wind, and a geomagnetic storm is likely to start at Earth within an hour or so.

Whether you will see auroras or not during the storm depends on how powerful it is, which determines how far from the poles the auroras will reach and how bright they will be. While the forecast is for a strong storm, we’ll just have to see…

At 2300 UTC (about one hour before this posting) you can see jumps occurred in many channels below. That means that the solar storm may begin right around now (0000 UTC, 8 pm New York Time)

POSTED BY Matt Strassler

ON September 16, 2024

A Good Night for Sky Gazing

[Update: indeed, both meteors and auroras are visible tonight, at least as far south as Massachusetts, so residents of northern-tier states should definitely be looking!]

Tonight, if the sky is clear and dark in your vicinity, would be a good night for staying up late, going outside, and looking up. Not that it’s an exceptional night for star gazing, necessarily; I wrote “sky-gazing” for a reason. The two phenomena you’re most likely to see are much, much closer than the stars. Both occur in the Earth’s upper atmosphere, and are generated by effects that occur within the solar system (i.e., the Sun, its planets, and their neighborhood.)

The phenomena in question? Meteors, for sure; and auroras, just maybe.

(more…)

POSTED BY Matt Strassler

ON August 11, 2024

Chance of Auroras in the Next 48 Hours

[Update July 30 8:00 am NYC time: there was a weak impact of a coronal mass ejection about 12 hours ago, but nothing big yet.]

After a few significant solar flares over the past few days, the chances of auroras (i.e. northern and southern lights) is high enough that it’s probably worth keeping an eye on polar skies for the next couple of nights. At the moment the forecast is for the best chances to be in Asia, but forecasting auroras is far from an exact science, and there could be surprises.

*The Aurora Borealis, or Northern Lights, shines above Bear Lake, Alaska. USAF photo: credit Senior Airman Joshua Strang*

To know when to start looking, I keep an eye on data from the ACE satellite. When a cloud of slow particles from a solar flare’s coronal mass ejection arrives, ACE’s data goes all haywire; you’ll see it as a sudden change in the plots’ appearance, as in the example shown below. ACE satellite sits 950 thousand miles [1.5 million kilometers] from Earth, and is located between Earth and the Sun. At that vantage point, it gives us (and our other satellites) a little early warning, of up to an hour.

Another good place to look is NOAA’s space weather dashboard. Its first panel, an example of which is shown below, displays three plots; the bottom plot is called “Geomagnetic Activity”. When that plot goes deep orange or red, then there’s probably some serious auroras going on in areas where they aren’t so often seen.

But be warned — the plot shows not what is happening now but what happened in a three-hour interval that is already past. If a geomagnetic storm is long enough, that’s still useful, but be aware that the data is out of date by the time we get to see it. That’s why the ACE satellite may well give you the best heads-up.

POSTED BY Matt Strassler

ON July 29, 2024

Nova, Nova, Supernova…

As has been widely reported, Earth’s inhabitants are looking forward to a rare event in the sky. It’s a “nova”, predicted to be visible sometime in the coming weeks.

The word “nova” is simply Latin for “new.” Coined during the Renaissance, it initially meant “a new bright thingy in the sky that isn’t just another Starlink satellite.” Nowadays it means a very particular type of new bright thingy.

But let’s not confuse it with a “supernova.” That’s something different. How different?

Nova: Your house has an electrical blackout for an hour
Supernova: Your entire city goes dark for a week

Nova: A meteor kills the dinosaurs and lots of other creatures
Supernova: A meteor melts the Earth and blasts part of it skyward to create the Moon

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POSTED BY Matt Strassler

ON July 29, 2024

Significant Chance of Major Aurora Outbreak!

[UPDATE May 10, 4:00 pm Boston Time, 10:00 pm EU time: AURORAS MAY BE ACTIVE NOW!]

I don’t use exclamation marks in blog post titles lightly. For those of us hoping to see the northern and southern lights (auroras) outside their usual habitat near the Earth’s poles, this is one of those rare weekends where the odds are in our favor. NOAA’s Space Weather Prediction Center has issued a rare G4 forecast (out of a range from G1 to G5) for a major geomagnetic “storm”.

Though the large and active sunspot from earlier this week has moved on, it has been followed by an even larger group of sunspots, so enormous that you can easily see them with eclipse glasses if you’ve kept your pair from last month.

*A monster sunspot group on the Sun right now (May 9, 2024).*

Powerful solar flares (explosions at the Sun’s visible surface) and the accompanying large coronal mass ejections (“CMEs”, huge clouds of subatomic particles that stream across space from the Sun toward the planets) keep coming, one after another; the second-largest of the week happened just a few hours ago. In the next 24-72 hours, the combined effects of these CMEs may drive the Earth’s magnetic field haywire, leading to northern and southern lights that are much stronger and much more equatorial than usual.

(more…)

POSTED BY Matt Strassler

ON May 10, 2024

Increased Chance of Northern/Southern Lights

A couple of days ago, I noted a chance of auroras (a.k.a. northern and southern lights) this week. That chance just went up again, with a series of solar flares and coronal mass ejections. The chance of auroras being visible well away from their usual latitudes is pretty high in the 36-48 hour range… meaning the evening of May 10th into the morning of May 11th in both Europe (with the best chances) and in the US and Canada.

Keep in mind that timing and aurora strength are hard to predict, so no prediction is guaranteed; it could come to nothing, or the auroras could show up somewhat earlier and be stronger than expected.

Meanwhile, the SciComm 2 conference continues at the Perimeter Institute. As part of it, experimental particle physicist Clara Nellist gave a public talk to an enthusiastic audience last night, reviewing the LHC experiments and their achievements. You can find it on YouTube if you’d like to watch it.

POSTED BY Matt Strassler

ON May 9, 2024

Quick Post: Eyes to the Skies

The Sun has been acting up; a certain sunspot has been producing powerful flares. In the past three days, several have reached or almost reached X-class, and one today was an X4.5 flare. (The letter is a measure of energy released by the flare; an X1 flare is ten times more powerful than an M1 class flare, and an X4.5 flare is almost three times more powerful than an X1 flare.)

*From the https://www.swpc.noaa.gov/ website*

With so much solar activity, it’s possible (though certainly not guaranteed) that one or more coronal mass ejections might strike Earth over the next 48 hours and might generate northern and southern lights (“auroras”). If you’re in a good location and the weather is favorable, you might want to check every now and then to see if the atmosphere is shining at you.

POSTED BY Matt Strassler

ON May 6, 2024

Running Circles Around One Another

Are you sitting or lying down? Perhaps you’re moving around at a walking pace? I probably am. And yet, unless you live in the northeastern US or in southern South America, you and I are moving relative to each other at hundreds of miles per hour.

In Chapter 2 of the book “‘Waves in an Impossible Sea”, I remarked on the this fact. (See below for the relevant passage.) At first glance it might seem puzzling. After all, the distance between your town and my town is constant; it never changes. And yet our relative motion is comparable to or faster than a jet aircraft. How can both of these things be true?

And then there’s another question: if we’re all moving so fast relative to one another, why don’t we feel the motion?

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POSTED BY Matt Strassler

ON May 2, 2024

DESI Shakes Up the Universe

It’s always fun and interesting when a measurement of an important quantity shows a hint of something unexpected. If yesterday’s results from DESI (the Dark Energy Spectroscopic Instrument) were to hold up to scrutiny, it would be very big news. We may well find out within a year or two, when DESI’s data set triples in size.

The phrase “Dark Energy” is shorthand for “the energy-density and negative pressure of empty space”. This quantity was found to be non-zero back in 1998. But there’s been insufficient data to determine whether it has been constant over the history of the universe. Yesterday’s results from DESI suggest it might not be constant; perhaps the amount of dark energy has varied over time.

(more…)

POSTED BY Matt Strassler

ON April 5, 2024

Total Eclipse a Week Away

I hope that a number of you will be able to see the total solar eclipse next Monday, April 8th. I have written about my adventures taking in a similar eclipse in 1999, an event which had a profound impact on me. Perhaps my experience might give you some things to think about that go well beyond the mere scientific.

Meanwhile, for those who can only see a partial solar eclipse that day, there’s still something really cool (and very poorly appreciated!) that you can do that cannot be done on an ordinary day! Namely, you can easily estimate the size of the Moon, and then quickly go on to estimate how far away it is. This is daylight astronomy at its best!

Side note for those in the Boston area: I’m speaking about my new book at Harvard on Wednesday April 3rd.

POSTED BY Matt Strassler

ON April 1, 2024

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Category: Astronomy

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

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