Space Weather

[Aelin]

On the previous solar cycle, wasn't the AR 2921, or a name like that which was the most active? Sun has decided the change obviously.

The "feather" size was more than 10 times the equateur size of the Earth, isn't it?  :nopanic;

[Jherrith]

For perspective 400,000 km is 248,548 miles

The distance from the Earth to the Moon is: 384,400 km or 239,900 miles

[Jherrith]

AN EXPLOSION ON THE FARSIDE OF THE SUN (UPDATED AGAIN): New images from the Solar and Heliospheric Observatory (SOHO) are giving us a better look at yesterday's farside explosion. SOHO coronagraphs recorded the most dramatic CME in years:



No, there won't be a geomagnetic storm. The explosion happened on the farside of the sun, so the CME is heading away from Earth. We dodged a bullet.


STEREO-A also observed a plume of plasma shooting up from the blast site. It was more than 400,000 km long.


Some readers have asked "How strong was the underlying solar flare?" We don't know. Solar flares are classified by their X-ray output, but there are no spacecraft on the farside of the sun with X-ray sensors. Best guess: It was an X-flare.

You might suppose that the farside of the sun is hidden from view. However, researchers using a technique called "helioseismology" can make crude maps of the sun's hidden hemisphere. Their latest map reveals a huge farside active region:



The black blob is a sunspot group--a big one--and it is the likely source of the explosion. According to Junwei Zhao of Stanford University's helioseismology group, active regions this large are rare. "This is only the second farside active region of this size since September 2017," he says.

Lucas Guliano, a solar scientist at the Harvard-Smithsonian Center for Astrophysics, believes the active region might be an old friend: AR2936, a sunspot that was on the Earthside of the sun in early February.

"If so, it is the same sunspot responsible for the geomagnetic storm that downed the SpaceX satellites on Feb. 4th," he says.

Apparently it has grown since then. Based on its current location, the sunspot could emerge into view over the sun's northeastern limb about 4 days from now. It could be quite a sight, so stay tuned.

[thelufias]

Not many foks do......that's for sure.

[Aelin]

Astronomers don't like that too

[thelufias]

Yes indeed..... He's created "Spacejunk R Us" :nopanic;

[Aelin]

Mother Nature and Space Father said stop to that "constellation"

[thelufias]

I missed this one.......

GEOMAGNETIC STORM AND RECENTLY DEPLOYED STARLINK SATELLITES


On Thursday, February 3 at 1:13 p.m. EST, Falcon 9 launched 49 Starlink satellites to low Earth orbit from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. Falcon 9's second stage deployed the satellites into their intended orbit, with a perigee of approximately 210 kilometers above Earth, and each satellite achieved controlled flight.

SpaceX deploys its satellites into these lower orbits so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag. While the low deployment altitude requires more capable satellites at a considerable cost to us, it's the right thing to do to maintain a sustainable space environment.

Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday. These storms cause the atmosphere to warm and atmospheric density at our low deployment altitudes to increase. In fact, onboard GPS suggests the escalation speed and severity of the storm caused atmospheric drag to increase up to 50 percent higher than during previous launches. The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag—to effectively "take cover from the storm"—and continued to work closely with the Space Force's 18th Space Control Squadron and LeoLabs to provide updates on the satellites based on ground radars.

Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth's atmosphere. The deorbiting satellites pose zero collision risk with other satellites and by design demise upon atmospheric reentry—meaning no orbital debris is created and no satellite parts hit the ground. This unique situation demonstrates the great lengths the Starlink team has gone to ensure the system is on the leading edge of on-orbit debris mitigation.

[thelufias]

Déjà maybe....we shall see....but very interesting....

[Jherrith]

SOLAR CYCLE 25--A DIFFERENT POINT OF VIEW: For much of the past year, the space weather community has been buzzing about the strong performance of young Solar Cycle 25 (SC25). Every month, sunspot numbers seem to blow past official predictions. This means we're about to have a strong Solar Maximum, right?

"Not so fast," cautions Dr. Ron Turner, an analyst at the ANSER research institute in Virginia. "It may be too early to anticipate a strong solar cycle."

This graph shows why Turner is skeptical:



Solar Cycle 25 is doing something interesting. It is mimicking old Solar Cycle 24 (SC24). "I took sunspot numbers from the early years of SC24 (the red dashed line) and overlaid them on SC25," says Turner. "They're an almost perfect match."

This is significant because Solar Cycle 24 went on to become the weakest solar cycle in a century. Its hot start did not lead to a strong maximum. Turner isn't saying that Solar Cycle 25 will likewise be a dud. But, rather, "these early sunspot numbers are not enough to guarantee a strong cycle."

Déjà vu, anyone?