poppy-does-science

[poppy-does-science]

The Hubble Space Telescope is Made Out Of Glass

But wait, Hubble is a reflecting, or Cassegrain telescope...

To not hold you in suspense, I will reveal that the glass is not intended to be seen through, and is coated with aluminium to provide the reflectivity. But then why use glass at all?

A mirror blank is initial material from which the telescope mirror is made, or the curved substrate that is often thinly coated with another material. In space telescopes, a commonly used material is ULE, or ultra-low expansion glass, which is what Hubble's primary and secondary mirrors are made out of. The curvature of this mirror is incredibly important, and just a tiny deviation can lead to the telescope being out of focus (as Hubble is familiar with). One possible cause of this is thermal expansion/contraction due to the change in temperatures when a telescope is launched into space.

Enter ULE. ULE has a very low coefficient of thermal expansion (CTE), meaning it doesn't expand or contract much when exposed to a range of temperatures. Along with being fairly strong and light, CTE one of the main reasons why Hubble's mirror is made out of glass.

Newer materials, such as Zerodur, have even smaller CTEs, and can even be tailored to be extremely stable in certain temperature ranges.

Pretty cool, huh.

[poppy-does-science]

Eyes On the Solar System: the coolest website that nobody seems to know about?

If you're interested in what is going on in our solar system, you NEED to visit this NASA webpage.

It has the most beautiful graphics on what's going on in the solar system, with planets, moons, asteroids, spacecraft and satellites able to be viewed in their current, past, and projected future positions! Zooming in on the Earth really puts into perspective how much STUFF we have orbiting our planet! You can see the planets in the background in this screenshot, and the Hubble Space Telescope. The perspective it gives you is unrivalled!

You can also increase the speed of time and watch everything move at an accelerated pace! It is absolutely mesmerising. I love watching Voyager and Pioneer from the date of their launches making their way outside the soalr system, and James Webb being launched and then settling into its place at Lagrange point 2 (BTW, a really good visualisation of L2!).

So yeah, I highly recommend! Find it at this link:

[poppy-does-science]

The Nancy Grace Roman Telescope is named after the Mother of Hubble

The Nancy Grace Roman Telescope (previously WFIRST) is a NASA mission set to launch in 2027. I think you guys need to know about more about it though, because although its technology is amazing, the most amazing thing about it is its name.

Dr Nancy Grace Roman was an executive at NASA, working as the Chief of Astronomy, Chief of Astronomy and Relativity, and Chief of Solar Physics (what cool job titles!!) from 1959 until her retirement in 1979. Among her many achievements (including being the first female NASA executive!), her most notable was Hubble.

Decades before people were ready to consider an investment such as Hubble, Dr Roman was pioneering for it, lobbying NASA officials to get it approved, putting together planning committees and fighting to secure funding.

Her dedication to Hubble earned her the nickname "Mother of Hubble". But I don't think this really emphasises her achievements enough. Hubble was the inspiration for so many space telescope missions, the mission that showed it was possible for the rest, the seed that sprouted so many more space telescopes, and so many more discoveries in our lifetimes.

By her own words “I think it would have existed sooner or later without me." But without her, how long would we have had to wait before this age of space telescopes? By being the Mother of Hubble, she has become the Mother of modern space-based astronomy.

The Nancy Grace Roman Telescope could not have a better name.

She often said, "for the price of one night at the movies each year, each American would receive 15 years of exciting discoveries." But she was wrong, because not just Americans, but people across the globe have now received over 30 years of discoveries!

Dr Nancy Grace Roman passed away on December 25th, 2018, three years to the date of the launch of the James Webb Space Telescope. I think she would be thrilled to see how far space-based astronomy has come.

Read more about her:

[poppy-does-science]

TIL that there is a group of 4 satellites orbiting the Earth studying how solar winds affect our planet. Their names are Rumba, Samba, Salsa, and Tango!!

Humans are so cute!!

[poppy-does-science]

The most expensive space telescope ever built is toxic!

The James Webb Space Telescope, costing 10 billion US dollars, is the largest (and most expensive) space telescope ever built. But did you know that its 6.5m diameter primary mirror is toxic?? It's made out of optical beryllium (AKA Be O-30), a particular form of the rare earth metal. And the fun thing about that is that it is toxic both as a skin irritant and as an inhalant. Inhaling beryllium dust can cause berylliosis, a disease with similar symptoms to pneumonia, as well as cancer. So no wonder that optical beryllium isn't commonly used to make space telescope mirrors!

[poppy-does-science]

genuinely confused how people can look out at the universe and not be overcome with a feral kind of wonder