Galactic habitable zone

Solar systems that can support life as we know it, we’ve learned, are not likely to be anywhere in a galaxy. Scientists, in 2021 believe some things …

  • The Milky Way Galaxy is a disk, with a greater density of stars and solar systems in the center
  • The Milky Way Galaxy is a bar spiral, in that it has two or four arms and a center mass
  • The Milky Way is around 100 million light years across
  • Stars at the outer edge of the arms are accompanied by fewer heavy atoms, like iron and carbon
  • Stars nearer the center of the galaxy are in a domain of high levels of radiation compared to the Sun

In our hippie past, we marveled at the Drake Equation, an attempt to illustrate the likelihood of life on another planet.

Asteroid 2000 QW7

Watch an Asteroid Fly by Earth Today in a Live Webcast from … › asteroid-flyby-september-2019-slooh-webcast

An asteroid known as 2000 QW7 is expected to pass by Earth closely, but safely, at 3.3 million miles (5.3 million kilometers) from Earth

NASA: Two asteroids will fly safely by Earth this week, so just … › news › nasa-two-asteroids-will-fly-safely-by-earth-…

NASA used this image of the far-off Vesta asteroid to illustrate its release on this week’s asteroids. NASA.

NASA news: NASA orbit video shows monster asteroid set to … › News › Science

The Asteroid, called 2000 QW7, was first discovered by NASA on August 8, 2000.

Large Asteroid 2000 QW7 to pass Earth – Comet Watch › large-asteroid-2000-qw7-to-pass-earth

On Saturday 14 September, 2019 a large asteroid (designated asteroid 467317 2000 QW7) will pass the Earth

Mars Mission 2020

Nasa will launch a mission to Mars in 2020. This may sound shocking until you learn that this will be another unmanned mission sending a robotic rover to explore the surface and perform experiments.

Manned Mission

The next manned mission to another terrestrial object will probably be a 2024 mission to the moon. We should be good at this, and it is good practice for manned exploration of other terrestrial destinations.

How soon?

The soonest time we might imagine a manned mission to Mars, even just for orbit, would be 2033 returning in 2035. The departure and return times would normally be about 26 months apart. Based on the orbit of the Earth and Mars, 26 months pass between minimums when travel time and energy required would be ideal. Travelling at the wrong time could increase the time and energy required by double. Ideal travel windows for the shortest possible mission (26 months) occur twice a century.

Consider that picking the ideal time would allow the mission to leave Earth and travel to Mars and return in just over 26 months. Picking the worst time for the mission could require in excess of five to ten years to complete.


A variable of great import in a trip to Mars is the type and quantity of fuel to use. To achieve the fastest travel time, you would want to accelerate until half way to Mars, and then decelerate until you land. You would need of course, to have plenty of fuel left to get home.

Asteroid 2019 OK

On July 24, 2019 an asteroid measuring between 60 and 140 meters in diameter whizzed by planet earth. It was the largest bolide to come between the Earth and the Moon this year. To compare, the Chelyabinsk meteor was estimated to be around 20 meters in size, where 1,491 injuries were reported according to Wikipedia.

Surprise asteroid whizzed by Earth today, and we didn’t even blink via @CNET

An asteroid just buzzed past Earth, and we barely noticed in time via @ConversationEDU

Asteroid 2019 OK to flyby Earth at 0.19 LD on July 25 – the largest of the year

Wolf Rayet 104

A Wolf Rayet star is larger than the Sun and two or there times hotter. It is suspected that some stars of this class are fusing heavier elements in their cores. They are identified by light emitted by ionised helium, nitrogen and carbon.

WR 104 is about 8500 light years from Earth. It is actually three stars, and part of a small nebula. Like our galaxy, which is sometimes called a pinwheel galaxy, Wolf Rayet is a pinwheel nebula. This might be evidence that celestial bodies from far away came close enough that their gravitational attractions bound them together and produced the pinwheel effect.

Interest in Wolf Rayet 104 is fueled by being near Earth, but also due to what we have learned about gamma ray bursts.

Fritz Zwicky

Born around 1900, just 10 years or so younger than Albert Einstein was a truly remarkable astronomer. The father of Dark Energy, Fritz Zwicky was the son of a Swiss Industrialist who lived in Bulgaria.

Dark Matter

Fermi-Lab scientists have spent the last 15 years or so searching for particles of Dark Matter. Using a disk of Gallium metal cooled to nearing zero Kelvin, scientists have not detected the particles. They sought out a particle with mass, traveling at less than the speed of light and unimpeded by other matter.

Missing Matter

Fritz Zwicky first referred to Missing Matter or Missing Mass when he observed galaxies at Mount Wilson, and calculated their mass and the speed of rotation. He found that stars near the edge of the galaxy sped around its center too quickly. Based on the gravitational pull of the galaxy, they should have been flung into space.