A View You’d See From An Asteroid’s Surface!

This scene, captured with a 35mm camera from inside the Space Shuttle Endeavour, shows Jupiter rising above the airglow over Earth’s horizon. The crescent Moon is at top frame.

Credit: NASA

Night sky

Lieksa, Finland

October 2018

Jupiter and 4 of her moons peaking out from behind our moon! 

Lunar Eclipse 2019

Image Credit: Zachary Wells

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I’ve found it!), but ‘That’s funny…’”

— Isaac Asimov | Author - I, Robot | Professor - Biochemistry

Stellar Winds

Stellar winds are fast moving flows of material (protons, electrons and atoms of heavier metals) that are ejected from stars. These winds are characterised by a continuous outflow of material moving at speeds anywhere between 20 and 2,000 km/s.

In the case of the Sun, the wind ‘blows’ at a speed of 200 to 300 km/s from quiet regions, and 700 km/s from coronal holes and active regions.

The causes, ejection rates and speeds of stellar winds vary with the mass of the star. In relatively cool, low-mass stars such as the Sun, the wind is caused by the extremely high temperature (millions of degrees Kelvin) of the corona.

his high temperature is thought to be the result of interactions between magnetic fields at the star’s surface, and gives the coronal gas sufficient energy to escape the gravitational attraction of the star as a wind. Stars of this type eject only a tiny fraction of their mass per year as a stellar wind (for example, only 1 part in 1014 of the Sun’s mass is ejected in this way each year), but this still represents losses of millions of tonnes of material each second. Even over their entire lifetime, stars like our Sun lose only a tiny fraction of 1% of their mass through stellar winds.

In contrast, hot, massive stars can produce stellar winds a billion times stronger than those of low-mass stars. Over their short lifetimes, they can eject many solar masses (perhaps up to 50% of their initial mass) of material in the form of 2,000 km/sec winds.

These stellar winds are driven directly by the radiation pressure from photons escaping the star. In some cases, high-mass stars can eject virtually all of their outer envelopes in winds. The result is a Wolf-Rayet star.

Stellar winds play an important part in the chemical evolution of the Universe, as they carry dust and metals back into the interstellar medium where they will be incorporated into the next generation of stars. 

source (read more) + Wolf–Rayet star

Studying physics is essentially being taught a simple structure, and then told ”actually, scratch that, the truth is actually far more complicated” over and over again until we reach the point where we still don’t know the truth, only that we do not have it.

In “Float” artist Susi Sie uses water and oil to create a whimsical landscape of bubbles and droplets. Coalescence is a major player in the action, though Sie uses some clever time manipulations to make her bubbles and droplets multiply as well. Watching coalescence in reverse feels like seeing mitosis happen before your eyes. (Video and image credit: S. Sie)

Thoughts and explanation about time travelling through a black hole?

A black hole curves the space-time fabric to an extreme point called singularity. And since space and time are working together, according to the theory of relativity, curvature and gravity also affect time.

This is best illustrated by one person (call them Unlucky) falling into a black hole while another person (call them Lucky) watches. From Lucky’s perspective, Unlucky’s time clock appears to be ticking slower and slower. This is in accordance with Einstein’s theory of general relativity, which (simply put) says that time is affected by how fast you go, when you’re at extreme speeds close to light. The black hole warps time and space so much that Unlucky’s time appears to be running slower. From Unlucky’s perspective, however, their clock is running normally and Lucky’s is running fast.

Comet C/2014 Q2 Lovejoy

by Joseph Brimacombe