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Dark Energy and Dark Matter

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Dark energy and dark matter

“Invisible matter which construct the universe: DARK MATTER”

The actual density of the luminous matter in the universe is just a few percent of percent. Adding in the mass equivalent of the radiation in the universe increases the density only a little. But is luminous matter—the stars and galaxies we see in the sky-the only matter in the universe ?Apparently not.
Very strong evidence indicates that a large amount of dark matter is also present; so much, in fact, that at least 90 percent of all matter in the universe is nonluminous. For instance, the rotation speeds of the outer star stars in spiral galaxies are unexpectedly high, which suggest that a spherical halo of invisible matter must surround each galaxy.
Similarly, the motions of individual galaxies in clusters of them imply gravitational fields about 10 times more powerful than the visible matter of the galaxies provides. Still other observations support the idea of a preponderance of dark matter in the universe. What can the dark matter be?
Dark matter bubble
The most obvious candidate is ordinary matter in various established forms, ranging from planet like lumps too small to support the fusion reactions that would make them stars, through burnt-out dwarf stars, to black holes. The snag here is that, in the required numbers, such objects would certainly have been detected already. Another possibility rooted in what we already know is the sea of neutrinos (over 100 million per cubic meter) that pervades space. Neutrinos appear to have mass, but very little, nowhere near enough to account for all the dark matter.
Indeed, if neutrinos were responsible for the dark matter, the universe could not have evolved to what it is today, galaxies, for example, would have to be much younger than they are. So neutrinos, too, may be part of the answer, but only part.

WIMPs and Axions

There is no shortage of other possibilities, all classed as cold dark matter, “Cold”. It’s means that the particles involved are relatively slow-moving, different, say, neutrinos, which constitute hot dark matter. Two main kinds of cold dark matter have been proposed, WIMPs and axions. WIMPs (weakly interacting massive particles) are hypothetical leftovers from the early moments of the universe.
An example is the photino, one of the particles predicted by the supersymmetry approach to elementary particles. The photino is supposed to be stable and to have a mass of between 10 and 109 GeV/c?, much more than the proton mass of 0.938 GeV/c?. Axions are weakly interacting bosons associated with a field introduced to solve a major difficulty in the Standard Model. WIMPs and axions are being sought experimentally, thus far without success.
The dark matter and dark matter needed to account for the motions of stars in galaxies and of galax-galaxies in galactic clusters brings the total density of the universe up to about 0.1pc. There may be still more dark matter.

Historical Development

In 1980 the American physicist Alan Guth proposed that, 10^-35 s after the Big Bang, the universe underwent an extremely rapid expansion triggered by the separation of the single unified interaction into the strong and electroweak interactions. During the expansion the universe blew up from smaller than a proton to about a grapefruit in size in 10^-30 s .
The inflationary universe automatically takes care of a number of previously troublesome problems in the Big Bang picture, and its basic concept is widely accepted. One of Guth’s conclusion was that the density of matter in the universe must be exactly the critical density Pc. If the inflationary scenario is correct, then, the universe is not only perfectly flat but as much as perhaps 99 percent, not merely 90 percent, of the matter in it is dark matter.
Finding the nature of the dark matter is clearly one of the most fundamental of all outstanding scientific problems.

Evidence of dark matter and properties of Dark Matter

Dark energy
The modern evidence for Dark Matter dates back to the early years of the last century. However, it is interesting to note that astronomical data had already faced a Dark Matter crisis before: in the 1840s, it was found that the data of the orbits of the planets in the Solar System was not consistent with the mass observed.
In particular, Uranus had an anomalous orbit. Le Verrier predicted a new source of matter that had not been detected before in the form of a new planet. He even predicted its orbit. This was discovered on the 31st of August of 1846. On the 23rd of September of 1846, Neptune was discovered. The Solar System had also an anomaly in the orbit of Mercury.
Le Verrier predicted an inner planet (Vulcan), and some observers claimed detection. But we know, this was not a real detection. Indeed, the orbit of Mercury is anomalous in Newtonian dynamics because of the need to include General Relativity corrections.
Hence, it was the theory of gravity that was going to fail. There is something that is important about these two examples, which is that Newtonian gravity which was not being accurate in two situations with two very different gravitational potentials (φN ∼ GM/r) and that the solution to one of the problem couldn’t fix the other one. For instance, General Relativity corrects Newtonian dynamics in situations where φN
corrections may be relevant.
The latter are very small for the outer planets. In the case of Dark Matter, we’ll also find a multi-scale phenomenology, that can be explained by a single hypothesis.

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An ambassador and trained facilitator under Eco Femme (a social enterprise working towards menstrual health in south India), Sanjina is also an active member of the MHM Collective- India and Menstrual Health Alliance- India. She has conducted Menstrual Health sessions in multiple government schools adopted by Rotary District 3240 as part of their WinS project in rural Bengal. She has also delivered training of trainers on SRHR, gender, sexuality and Menstruation for Tomorrow’s Foundation, Vikramshila Education Resource Society, Nirdhan trust and Micro Finance, Tollygunj Women In Need, Paint It Red in Kolkata.

Now as an MH Fellow with YKA, she’s expanding her impressive scope of work further by launching a campaign to facilitate the process of ensuring better menstrual health and SRH services for women residing in correctional homes in West Bengal. The campaign will entail an independent study to take stalk of the present conditions of MHM in correctional homes across the state and use its findings to build public support and political will to take the necessary action.

Saurabh has been associated with YKA as a user and has consistently been writing on the issue MHM and its intersectionality with other issues in the society. Now as an MHM Fellow with YKA, he’s launched the Right to Period campaign, which aims to ensure proper execution of MHM guidelines in Delhi’s schools.

The long-term aim of the campaign is to develop an open culture where menstruation is not treated as a taboo. The campaign also seeks to hold the schools accountable for their responsibilities as an important component in the implementation of MHM policies by making adequate sanitation infrastructure and knowledge of MHM available in school premises.

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Harshita is a psychologist and works to support people with mental health issues, particularly adolescents who are survivors of violence. Associated with the Azadi Foundation in UP, Harshita became an MHM Fellow with YKA, with the aim of promoting better menstrual health.

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MH Fellow Sabna comes with significant experience working with a range of development issues. A co-founder of Project Sakhi Saheli, which aims to combat period poverty and break menstrual taboos, Sabna has, in the past, worked on the issue of menstruation in urban slums of Delhi with women and adolescent girls. She and her team also released MenstraBook, with menstrastories and organised Menstra Tlk in the Delhi School of Social Work to create more conversations on menstruation.

With YKA MHM Fellow Vineet, Sabna launched Menstratalk, a campaign that aims to put an end to period poverty and smash menstrual taboos in society. As a start, the campaign aims to begin conversations on menstrual health with five hundred adolescents and youth in Delhi through offline platforms, and through this community mobilise support to create Period Friendly Institutions out of educational institutes in the city.

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A student from Delhi School of Social work, Vineet is a part of Project Sakhi Saheli, an initiative by the students of Delhi school of Social Work to create awareness on Menstrual Health and combat Period Poverty. Along with MHM Action Fellow Sabna, Vineet launched Menstratalk, a campaign that aims to put an end to period poverty and smash menstrual taboos in society.

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A Computer Science engineer by education, Nitisha started her career in the corporate sector, before realising she wanted to work in the development and social justice space. Since then, she has worked with Teach For India and Care India and is from the founding batch of Indian School of Development Management (ISDM), a one of its kind organisation creating leaders for the development sector through its experiential learning post graduate program.

As a Youth Ki Awaaz Menstrual Health Fellow, Nitisha has started Let’s Talk Period, a campaign to mobilise young people to switch to sustainable period products. She says, “80 lakh women in Delhi use non-biodegradable sanitary products, generate 3000 tonnes of menstrual waste, that takes 500-800 years to decompose; which in turn contributes to the health issues of all menstruators, increased burden of waste management on the city and harmful living environment for all citizens.

Let’s Talk Period aims to change this by

Find out more about her campaign here.

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A former Assistant Secretary with the Ministry of Women and Child Development in West Bengal for three months, Lakshmi Bhavya has been championing the cause of menstrual hygiene in her district. By associating herself with the Lalana Campaign, a holistic menstrual hygiene awareness campaign which is conducted by the Anahat NGO, Lakshmi has been slowly breaking taboos when it comes to periods and menstrual hygiene.

A Gender Rights Activist working with the tribal and marginalized communities in india, Srilekha is a PhD scholar working on understanding body and sexuality among tribal girls, to fill the gaps in research around indigenous women and their stories. Srilekha has worked extensively at the grassroots level with community based organisations, through several advocacy initiatives around Gender, Mental Health, Menstrual Hygiene and Sexual and Reproductive Health Rights (SRHR) for the indigenous in Jharkhand, over the last 6 years.

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A Guwahati-based college student pursuing her Masters in Tata Institute of Social Sciences, Bidisha started the #BleedwithDignity campaign on the technology platform, demanding that the Government of Assam install
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